[QUOTE]Originally posted by Razorback1980
<i><b>I started this thread to find out who offered the best replacement parts to replace an entire system for one that was probably past it's normal life. Just to find out if anyone had any experience replacing their whole system. </b></i>

OK. I'll attempt to answer your original question from a supply side view, and not digress on other facts.

Most of the "compressor" kits have key components, such as a compressor, drier and hose assemblies or fittings for hose assemblies. There are two types of compressors that are usually sold in these kits, wobble plate and swash plate. A wobble plate would be atypical Sanden 507, 508 (most common models) compressor as found in the aftermarket kits for the 911/930 to replace the crankshaft pre 84 York's. Wobble plates, which you can explore on the internet to save band width here, have pistons mounted on one side of the plate that is mounted on the shaft. The wobble plate "wobbles" to move the pistons back and forth. The swash plate such the Kuehl brand, has pistons on both sides of the wobble plate. Both will pump as needed however the swash plates then to run smoother. The Nippondenso, that originally came on your car, is a swash plate design. A "wobble" plate is not "stale news" in that they perform well, they are reliable and easily serviceable. Most suppliers of these kits do not cut off the "extra" mounting ear as one reader noted; usually the marketer of the package leaves the "extra" ear on the compressor as the compressor may have more than one application; cutting off the ear can take 5-15 minutes depending upon your tools. When xx supply a compressor with an extra mounting ear xx forewarn the installer about cutting off the ear to clear the sway bar. Most kits include a drier and orings. Most kits include the necessary brackets to adapt the compressor to the 944's alt/comp casting mount, however some suppliers provide better adapter brackets than others and some provide yellowcad plated hardware vs. yellow zinc. Most kits include all the nuts and bolts. Where kits start to vary is with the compressor to condenser hose, whereas some a complete barrier hose assembly and some marketers provide a hose with barbs and clamps (it is not adviseable to "barb and clamp" a high side line, however I know someone will respond that they did it and the world is rosey). Some suppliers have good detailed pictorial instructions, some have sketches. Some suppliers have R134a charge port adapters, some don't and some have poor quality ones. Some suppliers include the conversion sticker which you should put on and some don't. Some suppliers tell you how much oil is in the compressor and how much they know from experience works, and they advise you to check just in case, while others don't touch the subject of oil. Some suppliers provide reasonable tech support and some might get back to you in a week or so.

I am not aware of any supplier currently marketing a "complete system" and I would question anyone which attempted to agree with you that you need to approach the solution in that fashion with a 944 (911's and 930's are a different animal). That is not to say it can't be provided. Maybe some of these notes from a supplier will give you an idea why you won't want throw your money away but rather look at it from a different point of view and ask "why is it sold or not sold":

1) Evaporators in these cars fail "seldom". If we receive 1000 phone calls a year on 944 ac, not more than 5 would ask about the evaporator. Of those 5 requests only 1 would be a qualified sale, meaning the guy really needs and evaporator. They simply don't fail as often as say a 911 or 964/993/993.
2) Expansion valves in these cars fail "seldom". If we receive 1000 calls a year on 944 ac, not more than 50 will ask for an expansion valve. Of the 50 specific requests I would guarantee you that 40 of them are because "my shop told me I should replace the expansion valve cause that's what they do". Of those 40 shops I can guarantee you that most of them are doing it because they think it is a good practice (even though the valve is functioning perfectly). Of the 10 remaining retail "do-it-youselver's" who ask for a valve, 8 of them "heard that they should replace it" (even though the valve is functioning perfectly).
Of the 2 customers who will purchase a valve regardless of our advise, 1 will want to return it and the other will find someone else to attempt to install it.
3) AC hoses. The usual culprit is the compressor to condenser hose as stated before hand, this is the hose that usually fails first. The next to go and that does not mean the next day, is drier to expansion valve hose line assembly (heat and pressure) and then the condenser to drier hose. The evaporator to compressor hose does fail in the rubber section however by that time most customers usually need a new compressor and if they are buying atypical "kit" it includes a cut off barb and clamp solution. Why does everyone not replace this last hose,
take a look at where it is and you'll find your answer.
4) If the compressor has not leaked or failed by now, I mean by the year 2006, then the car must be a real garage queen, probably 1 out of 100. By now most of these cars have over 100k on the compressor and I'd be suprised if over 50% have not been "resealed" by now. When they start reaching 100k miles in hot climates then the compressor is literally shot. By shot we mean worn pistons, cylinders bores and "wobble plate". You cannot resleeve them or replace the wobble plate economically.
Anything that is "rebuilt" out there is frankly questionable.
I know because we use to rebuild them 24/7 and frankly the years rolled on we threw away more cores than you can fit in dump truck. That is why there are "kits" that include new aftermarket compressors.
5) Condensers fail now for three reasons: bullet holes and clumsy wrenches. However as time marches on corrosion will be more common. There is available a high performance serpentine drop in replacement model to resolve the replacement part issue and improve on performance.
6) From a suppliers experience, the successful "compressor kit" with its accessories as packaged by a particular marketeer, tend to be more favorable because they solve 90% of the 944 ac problem. The "package" is based on years of experience from listening to what the market needs and wants: what the 944 shop installer's (who have more experince naturally than the occasional do-it-yourselfer) want, what the retail client needs and what the average client can afford to solve the problem reasonably.

I hope these comments help to anwer your primary question regarding <i>replacement parts to replace an entire system</i>, from the supply point perspective. Our previous posts where only meant to keep you on track, you should not take offense.

Good luck in your quest.

Well, that was definitely better than the "take it to the shop" because we morons here aren't capable for one reason or another of working on a/c. Just so you know...been there, done that. They used Porsche OEM parts which is why I questioned you recommending that. I spent over five thousand dollars to get the a/c on my 86 944 working and it didn't come out any better than the work I've done on my own with my other cars, so I have no interest in doing that again with my 87. That's why I tend to do things myself and look to others for any experience (such as how long a particular brand of aftermarket compressor lasted over another) or tools I may not have access to but mostly to see what experiences people have had and if I should stay away from one particular kit or another. As you and one of the other posts mentioned, they are not all the same and I want a top quality solution and not something I have to grind and custom fit. Of course there are some people here that don't do some things to their own cars like a/c but I don't think that's the majority of us and if they wanted, we would help them as best we can so they can get theirs working without spending as much money as I did. And they in turn help me by offering up solutions such as duracool that it seems everyone that posted had good things to say about the product... except you. This is my daughters car and I want her to be able to drive it for the next ten years or so while finishing high school and college with the fewest amount of problems, so it seems logical to come up with an a/c solution for the long term because we run the a/c almost every day of the year here in Texas. The point I was trying to make is should I replace the expansion valve while I'm in the dash (for a different reason) because it's difficult to get to. What I'm reading (and correct me if I'm confused) is that in your opinion, there is no need to replace the expansion valve unless I allow the compressor to deterioriate causing it to send particles into the a/c lines. Okay, so this is good news as I wasn't looking forward to replacing that part even though I'm going to have the dash out anyway. The question going through my mind right now is...with other systems the warranty is void on the compressor unless you put in a new orifice tube or expansion valve, yet you say they typically don't need to be replaced. Can you explain why others require a new orifice tube or expansion valve for them to honor the warranty on the compressor? Not trying to be mean in any way, just want to know why other manufacturers have different recommendations than you.

So, what I'm hearing from a supplier's point is that I should replace the compressor with a high quality kit from somewhere that includes most of what I need and while I'm doing everything replace any hoses that may leak the new refrigerant or have rubber parts as they have probably deteriorated over time making sure I use high quality hoses especially on the high side. I definitely agree with you on that...on the high side, good quality hoses are a must. I may also consider replacing the condensor not because it's bad but more from the extra efficiency that could be gained to help relieve some of the stress on the compressor due to Texas heat....especially if I'm looking for a long term trouble free solution. Put it all back together and check for leaks. Sound pretty close to what you think?

What might be helpful would be some posts on how to properly install the Griffith's a/c products. You know like how to install a new compressor kit including tips on how to make sure no leaks appear at the joints, vacuum and charging procedures, and how to determine if everything is working properly after installation. That is something I think everyone would like to read. You could even post it over on the technical section for everyone to refer to. Just a thought.

Regards

Your initial question in this particular forum, I thought was unique as there is very little in the way of 924s/944/968 ac comment as compared to the 911/930 forum. And I'm sure the founders would enjoy and want to see the thread continue.


[QUOTE]Originally posted by Razorback1980
<i> <b> I spent over five thousand dollars to get the a/c on my 86 944 working and it didn't come out any better than the work I've done on my own with my other cars, so I have no interest in doing that again with my 87. </i></b>
That is interesting. Maybe you can share your experience in more detail.

<i> <b>
That's why I tend to do things myself and look to others for any experience </i></b>
OK

<i> <b>
or tools I may not have access to
</i></b>
I think i mentioned a brief list already, however if you need more details simply PM your request to save on bandwidth.

<i><b> if I should stay away from one particular kit or another</i></b>
Stay away from "recharging kits", as mentioned in the thread, as they typically do not include everything the average user needs. (see above note on tools).

<i><b>Of course there are some people here that don't do some things to their own cars like a/c but I don't think that's the majority of us and if they wanted, we would help them as best we can so they can get theirs working without spending as much money as I did. </i></b>
I agree whole heartedly. And more importantly "time" is sometimes more valuable than greenbacks (life is too short).

<i><b>
And they in turn help me by offering up solutions such as duracool that it seems everyone that posted had good things to say about the product... except you. </i></b>
Asked and answered.

<i><b>
This is my daughters car and I want her to be able to drive it </i></b>
I have two daughters and two sons.
I would never give them or service their (nor my) cars with something, in my opinion, increased the risk of fire
or otherwise, such as having a flammable vapor located in a condenser in the front of the car where ignition of the product is very probable upon frontal impact.
Here is an example taken from another forum which described a fireball as "flammable refrigerant" fire:
http://forums.pelicanparts.com/uploa...1138715380.jpg
Naturally "something" lead up to this event, but in life
something always leads up to it sooner or later.
Though I have addressed this issue in the thread,
other readers are welcome to read more about it here:

http://forums.rennlist.com/rennforums/showthread.php?t=145159&page=1&pp=15
http://www.epa.gov/ozone/snap/refrigerants/hc12alng.html#q8
http://ptcl.chem.ox.ac.uk/MSDS/CY/cyclopentane.html

<i><b>The point I was trying to make is should I replace the expansion valve while I'm in the dash (for a different reason) because it's difficult to get to. </b></i>
The difference in R12 vs. R134a expansion valves is primarily the "superheat" settings. A R12 vs. a R134a valve is insignificant in this threads application in terms of superheat, however the superheat range should be maintained. I, personally, would only replace the valve (in a 944 and the alike family) if it has been confirmed to be dysfunctional or probable to lead to failure as shown
by an inspection of the upline system for contamination (after the drier). However, if you are going into the dash
to repair or replace something else it would be logical
to apply the "might as well" attitude, and inspect the valve
while you are there.


<i><b>What I'm reading (and correct me if I'm confused) is that in your opinion, there is no need to replace the expansion valve unless I allow the compressor to deterioriate causing it to send particles into the a/c lines.
</i></b>Based on the number of requests which have been "qualified" (meaning the client knows the valve is dysfunctional or is suspect to future contamination) we find very very few instances where the valve needs to be replaced in a 944 family system (refer back in the thread).

<i><b>
The question going through my mind right now is...with other systems the warranty is void on the compressor unless you put in a new orifice tube or expansion valve, yet you say they typically don't need to be replaced.
</i></b>
Yes, some suppliers or manufacturers mandate replace of the valve. So read your limited warranties.

<i><b>
Can you explain why others require a new orifice tube or expansion valve for them to honor the warranty on the compressor? </i></b>
Most of the P cars, as I recall, use "expansion valve systems" which are typically differentiated from other system designs by having a drier. "Orifice tube systems"
usually have an accumulator. There are two potential problems that can occur with a failing valve or tube, and think of it like a carburetor on the engine for simple terms:
1) Running too lean, whereas the valve is constantly closed or not opening enough to allow refrigerant to carry
oil back to the compressor, which would lead to compressor seizure. or
2) Running to rich, whereas the valve is constantly stuck open flooding the evaporator core and further flooding the compressor with liquid rather than vapor. Depending upon the controls designed in the system, the ambient or condition at the time and so forth, the excess liquid refrigerant could, as they say "liquid slug" the compressor and damage the valves and unit.

<i><b>
Not trying to be mean in any way, just want to know why other manufacturers have different recommendations than you. </i></b> I can't answer for other firms warrranty terms and conditions, and I think if you read their warranty statements in greater detail you may find more additional information. It is our experince that failure of the product is most likely to occur when the person servicing the system failed to follow or overlooked good practices. I don't recall stating that you should never replace a valve. What we state acutally covers more of the bases. I'll paraphrase it in a condensed form:
<i>When installing the compressor in a vehicle with a failed compressor it is mandatory to: (i) determine the cause of failure and (ii) correct the problem prior to installing/operating the replacement compressor. </i>
Believe it or not some retail customers and a few shops simply ignore good working practices and think their credit card company's terms and conditions will salvage their
laziness.
And,
<i>All system components and lines must be properly decontaminated to remove internal particles & debris before installing the replacement compressor </i>.
Once again, logical procedure.
And,
<i>Liquid flushing does not guarantee removal all contaminants</i>
Some clients go the internet and buy something a can of liquid flush and a $49.00 pressure container and expect
that just because they attempted the cleaning procedure that it works 100% of the time.
And
<i> The installer is responsible to verify the amount of oil in the compressor and system (since ac systems don't have oil dip sticks, and you can never assume the amount of oil supplied if any in any compressor from any supplier).</i>
And
<i>Compressor failure caused by abnormal systems, improper installation, application or maintenance voids all warranties</i>
No compressor is 100% bulletproof.
Remember that compressors (for this component topic)
are like "engines" and typically the manufacturer's warranty concerns follow the same product avenue.

<i><b>
So, what I'm hearing from a supplier's point is that I should replace the compressor with a high quality kit from somewhere that includes most of what I need
</i></b> Well naturally YES. But then you have the
problem from the suppliers perspective as to what to package in the kit vs. what the market is willing to
pay. If a supplier dreams up a "cover all bases 'x' product kit" chances are the price could be higher than most clients are willing or can afford to pay (and we have a few product kits dedicated to that specific client; the savvy perse client, experienced installers, that have been-there-done-that). Unfortunately for the retail client
there are companies that try to market on price only (cutting corners on details and tech support), what we call the W-Mart guys who "can beat anyone's price", so you get what you pay for as with any product or service.


<i><b>I may also consider replacing the condensor not because it's bad but more from the extra efficiency that could be gained to help relieve some of the stress on the compressor due to Texas heat....especially if I'm looking for a long term trouble free solution. Put it all back together and check for leaks. Sound pretty close to what you think? </i></b> Looks like you now have your GPS up and running.

<i><b>
What might be helpful would be some posts on how to properly install the Griffith's a/c products. You know like how to install a new compressor kit including tips on how to make sure no leaks appear at the joints, vacuum and charging procedures, and how to determine if everything is working properly after installation. That is something I think everyone would like to read. You could even post it over on the technical section for everyone to refer to. Just a thought. </i></b>. I would agree and appreciate the
kind thoughts. Guess well have to have a few Becks
and think that one over ;>)

I agree 100%. IIRC the Nippondenso compressors use carbon-faced seals that are horrendously leak-prone. I once had a very experienced a/c guru put it this way, "those things will leak if you so much as look at 'em funny". The Sanden unit I use on the early 944 is MUCH better (has never leaked). Don't know what kind of seal it uses in the front, but whatever it is, it's 100% leakproof as compared to a half-dozen Nippondenso units that have blown out at one time or another in my various sordid experiences. . .

Not necessarily saying they're the best and no affiliation, but I'm happy with their product. If this compressor goes on the 951 (a 'denso), I'll be buying a Sanden for that one too.

That's a good point. And here is another to consider with it from a "rebuilders" perspective....

The "carbon" is not the primary cause of failure.

There is one (1) primary source manufacturer that most ac component (parts suppliers) distributors use. That is not say there are not more, however the market is dominated by one. I recall one day getting in a shipment of 100 units and noting the first 3 out of the carton had something impregnated in the oring when we started to install them. Next came a 100% inspection, prior to installation, of every seal in the box and back tracking every seal in inventory, which lead to numerous phone calls to the supplier ... who also had to follow the same precautious steps.

The carbon bearing seal, somewhat alike the old fashion water pump seal design, does work well when it is installed properly (this based on remanufacturing over 1.5k 10P15 and 6E171 Nippon base models). The 944 used the 6E171 in the 85/1 and switched to 10P15E with the 85/2; we'll ignore the less common later years for the moment. The same carbon type "bearing" is used in an "millions" of compressors. Interesting side note about the early 85/1 compressors (aka 6E171) they have steel cylinders and replaceable rings on the pistons, whereas the later 85/2 (10P15E) is the "Vega engine" of the ac world. It has aluminum cylinders and aluminum pistons, no rings, not serviceable, throw it away. However, this is common with most wobble and swash plate designs from other manufacturers besides what is discussed here.

The carbon's roll in the seal function is a "bearing surface", it (for simple terms) sits in a spring loaded "carrier" along with the outer shaft diameter oring. This carrier runs on the shaft. Opposing the carrier is a polished race. The race has an o-ring on its outer diameter. The sealing effect basically works this way, the carrier's o-rings seals the shaft and the race's o-ring seals the compressor nose. As pressure is exerted onto the carrier, the o-ring tightens up on the shaft.

The o-ring, as well as any other type of contact seal, fails in time, like any other elastomer, due to pressure, contaminants, and "rust". Rust forms on the shaft when moisture works its way past the clutch assembly and lays in front of the seal assembly. Or, it can arrive in the form of moisture in the system (internally; the role of the drier attempts to ward off). The compressor shaft in this area, when rusted, tears up the seal and creates pits which allow for bypass.

The biggest problem when replacing the carbon bearing type seal assembly is in the handling; knowing how to set and align (in some designs) the carrier on the shaft as well as properly setting its mating race in the nose. You have to handle the carrier with some care. There is an old wives tale that says "if you get a finger print on the carbon or the race, then it will fail". Not true. However, if you leave a "dirty" finger print that has grit on it then naturally it will grind down things real fast.

As I recall, the 964 and 993 do not use a carbon carrier, but more of a "contact seal" design, and frankly I see just as many nose seal failures in retrospect to the numbers in the market as 944 familys.

Both the Sanden wobble plate and the various other brand swash plate compressors work "reasonably well" when maintained. I think rather than say one particular design or manufacturer is more reliable than the other, I would first consider the application of the product in a particular system and look at the ratio of failures for those particular systems rather than the particular compressor itself.

In terms of reliability you also have to consider whether we are looking at non-P daily drivers or exclusively at a narrow group of a particular design or make which is in the range of 20 years old, of which their ac systems seldom ever get the proper attention until they break. In comparison, consider how much attention we give to the oil filter, air filter, octane rating of fuel and the AFR going on in the engine.

Or the case of a compressor that ran well for 15-20 years and trying to compare it against one that replaced it just a few years ago. ;>)

Wow, so much information in this thread!
I am working on the A/C in a friend's car this spring, and my advice was to have all rubber hoses rebuilt (there is a shop that will cut and crimp new rubber sections into them), and to replace the compressor (which is visibly leaking out of the front seal). The next part of my advice was to help increase cooling efficiency, and that was to replace the condensor with one of the serpentine units from Griffiths.
When his system was operating, both high and low side pressures were within spec (using R-12 substitute Duracool), so I think the expansion valve is just fine.


Anyways, I saw that picture of the refrigerant fire up above, and am wondering one thing....
Here we are being told not to use hydrocarbon refrigerants, because they are too flammable, and yet they are actually less flammable than R134. Why are we being told not to use them??

[QUOTE]Originally posted by Razorback1980
<i> <b> I spent over five thousand dollars to get the a/c on my 86 944 working and it didn't come out any better than the work I've done on my own with my other cars, so I have no interest in doing that again with my 87. </i></b>
That is interesting. Maybe you can share your experience in more detail.

Ok, when my compressor gave way, it did so with a loud noise resulting in hot air coming in the car very quickly. I took it to my local a/c specialist who was going to replace the compressor but he told me that it had distributed a black substance throughout the entire system and his flush wasn't able to clean it all out. He said every time he flushed it, black stuff just kept coming. The only solution he offered was to replace the entire refrigerant system with new clean parts other than the switches. Since i wanted a reliable system, I went ahead with the repair and he put on all new Porsche OEM parts resulting in a bill of approximately 5 grand. He said the compressor alone was 1800 dollars from Porsche and of course by replacing everything, labor costs were pretty high as well. It worked when I got it back, but that's when I figured out that I could swap parts as well as the next guy and save the labor costs. BTW, this was in 89. Since then, I have educated myself through friends that work on a/c systems for a living and I'm going to do the 87 by myself.

<i><b> if I should stay away from one particular kit or another</i></b>
Stay away from "recharging kits", as mentioned in the thread, as they typically do not include everything the average user needs. (see above note on tools).

We'll have to agree to disagree on this one. I think there are times when it's okay to use them. But certainly not to diagnose problems.

<i><b>Of course there are some people here that don't do some things to their own cars like a/c but I don't think that's the majority of us and if they wanted, we would help them as best we can so they can get theirs working without spending as much money as I did. </i></b>
I agree whole heartedly. And more importantly "time" is sometimes more valuable than greenbacks (life is too short).

I hear what you are saying and if those are not your priorities in life, that's okay but that's what I was talking about where your opinions are so different than mine. I certainly can't speak for everyone on here but I enjoy working on my 944 and I really like knowing exactly what was done and not done. I don't necessarily enjoy the Grand Prix as much as that's just a car, but I feel very differently about my 944....even after owning it for 20 years. There is also a trust issue as not everyone is capable of working on these cars although there are many garages that tell you they can work on anything. So, it's also kind of a trust thing....I don't want to be one of those people that put out a post that says I can't get my oil drain plug out with a three foot pipe wrench because someone else changed my oil. Nobody cares about my car like I do....including that a/c specialist.

<i><b>
This is my daughters car and I want her to be able to drive it </i></b>
I have two daughters and two sons.
I would never give them or service their (nor my) cars with something, in my opinion, increased the risk of fire
or otherwise, such as having a flammable vapor located in a condenser in the front of the car where ignition of the product is very probable upon frontal impact.

Warning taken, but I'm sure that you have driven many cars with R12 as the a/c refrigerant, I know I have...of course reducing the risk of fire is always a good thing, I think we can agree on that. I'm still keeping duracool as an option if I need it. Again, we'll have to agree to disagree. Does that mean that you drive your car without gasoline...in a front impact, it could go up as well and does many many more times than freon or a substitute. Buddy of mine had his 944 turn from red to black in an instant because oil leaked from the camshaft seal directly on the headers....I'm not going to drive mine without oil either although it would take away that risk of a fire. But I appreciate the warning about the flammability. Information which can be used in evaluating whether duracool is right for us or not. Personal choice and neither yours nor mine are the right choices for everyone.

Sorry, this post was too long, so I had to do it in three sections....

<i><b>The point I was trying to make is should I replace the expansion valve while I'm in the dash (for a different reason) because it's difficult to get to. </b></i>
The difference in R12 vs. R134a expansion valves is primarily the "superheat" settings. A R12 vs. a R134a valve is insignificant in this threads application in terms of superheat, however the superheat range should be maintained. I, personally, would only replace the valve (in a 944 and the alike family) if it has been confirmed to be dysfunctional or probable to lead to failure as shown
by an inspection of the upline system for contamination (after the drier). However, if you are going into the dash
to repair or replace something else it would be logical
to apply the "might as well" attitude, and inspect the valve
while you are there.

That's one of the decisions I'm considering for the replacement is whether to do most of the system including the expansion valve. I wasn't so concerned about the superheat settings part, but you made a good point. What I was thinking is if it's new, it might be less prone to fail in the future. I know if it is not functioning properly, it will make the compressor work harder and fail sooner. While I hate cracking open joints, it seems to me the best thing to do is just replace it while I'm there and leak check it before I put the dash back in. At least you know the condition of the valve at that point. I guess it's still good policy to check it after the a/c system is running just to make sure it's working properly...even new parts fail to work properly occasionally.

<i><b>What I'm reading (and correct me if I'm confused) is that in your opinion, there is no need to replace the expansion valve unless I allow the compressor to deterioriate causing it to send particles into the a/c lines.
</i></b>Based on the number of requests which have been "qualified" (meaning the client knows the valve is dysfunctional or is suspect to future contamination) we find very very few instances where the valve needs to be replaced in a 944 family system (refer back in the thread).

So what I'm reading is that if I don't already have the dash out and want to convert my system to 134, probably no need to pull the dash and replace it unless some testing has proven it needs to be. Point well taken as someone mentioned in a previous thread, the a/c specialist they used decided it needed to be changed. Guess everyone has an opinion on that one.

<i><b>
Can you explain why others require a new orifice tube or expansion valve for them to honor the warranty on the compressor? </i></b>
Most of the P cars, as I recall, use "expansion valve systems" which are typically differentiated from other system designs by having a drier. "Orifice tube systems"
usually have an accumulator. There are two potential problems that can occur with a failing valve or tube, and think of it like a carburetor on the engine for simple terms:
1) Running too lean, whereas the valve is constantly closed or not opening enough to allow refrigerant to carry
oil back to the compressor, which would lead to compressor seizure. or
2) Running to rich, whereas the valve is constantly stuck open flooding the evaporator core and further flooding the compressor with liquid rather than vapor. Depending upon the controls designed in the system, the ambient or condition at the time and so forth, the excess liquid refrigerant could, as they say "liquid slug" the compressor and damage the valves and unit.

I know how they work, but that wasn't the question. I am guessing the answer is that the manufacturer is given some level of trust the expansion valve/orifice tube was not the reason for their new compressor to fail if a failure does occur.

Last part, I promise....

<i><b>
Not trying to be mean in any way, just want to know why other manufacturers have different recommendations than you. </i></b> I can't answer for other firms warrranty terms and conditions, and I think if you read their warranty statements in greater detail you may find more additional information. It is our experince that failure of the product is most likely to occur when the person servicing the system failed to follow or overlooked good practices. I don't recall stating that you should never replace a valve. What we state acutally covers more of the bases. I'll paraphrase it in a condensed form:
<i>When installing the compressor in a vehicle with a failed compressor it is mandatory to: (i) determine the cause of failure and (ii) correct the problem prior to installing/operating the replacement compressor. </i>
Believe it or not some retail customers and a few shops simply ignore good working practices and think their credit card company's terms and conditions will salvage their
laziness.
And,
<i>All system components and lines must be properly decontaminated to remove internal particles & debris before installing the replacement compressor </i>.
Once again, logical procedure.
And,
<i>Liquid flushing does not guarantee removal all contaminants</i>
Some clients go the internet and buy something a can of liquid flush and a $49.00 pressure container and expect
that just because they attempted the cleaning procedure that it works 100% of the time.
And
<i> The installer is responsible to verify the amount of oil in the compressor and system (since ac systems don't have oil dip sticks, and you can never assume the amount of oil supplied if any in any compressor from any supplier).</i>
And
<i>Compressor failure caused by abnormal systems, improper installation, application or maintenance voids all warranties</i>
No compressor is 100% bulletproof.
Remember that compressors (for this component topic)
are like "engines" and typically the manufacturer's warranty concerns follow the same product avenue.

All information we already know but better than take it to the garage....so please continue on..inform us about the proper installation of the 944 a/c system and how to do it properly according to Griffiths specifications....that would be good information that we may or may not know.

<i><b>
So, what I'm hearing from a supplier's point is that I should replace the compressor with a high quality kit from somewhere that includes most of what I need
</i></b> Well naturally YES. But then you have the
problem from the suppliers perspective as to what to package in the kit vs. what the market is willing to
pay. If a supplier dreams up a "cover all bases 'x' product kit" chances are the price could be higher than most clients are willing or can afford to pay (and we have a few product kits dedicated to that specific client; the savvy perse client, experienced installers, that have been-there-done-that). Unfortunately for the retail client
there are companies that try to market on price only (cutting corners on details and tech support), what we call the W-Mart guys who "can beat anyone's price", so you get what you pay for as with any product or service.

Okay, again all information anyone with a set of keys already knows....keep going though, you're getting closer. Try something like this...if your compressor completely blows, then do step one, two, three to determine just how much you should replace in the system...After you get the parts, do step four, five and six to replace these parts. You know, guidelines to follow to help figure out how much to replace or not replace from a supplier's perspective. All this is way too high level for what this forum is generally looking for. Details, Details. Good procedures to follow, that's what we want.


<i><b>I may also consider replacing the condensor not because it's bad but more from the extra efficiency that could be gained to help relieve some of the stress on the compressor due to Texas heat....especially if I'm looking for a long term trouble free solution. Put it all back together and check for leaks. Sound pretty close to what you think? </i></b> Looks like you now have your GPS up and running.

Okay, so that part wasn't rocket science and any six year old could have figured that out.

<i><b>
What might be helpful would be some posts on how to properly install the Griffith's a/c products. You know like how to install a new compressor kit including tips on how to make sure no leaks appear at the joints, vacuum and charging procedures, and how to determine if everything is working properly after installation. That is something I think everyone would like to read. You could even post it over on the technical section for everyone to refer to. Just a thought. </i></b>. I would agree and appreciate the
kind thoughts. Guess well have to have a few Becks
and think that one over ;>) [/B][/QUOTE]

Not too many of those Becks as we want ALL the steps put in there...no shortcuts. :-) Besides, I work in a computer lab all day, gotta watch those calories so I don't bend the fender when I lean over it replacing my a/c parts. Put me down for a Bud Light. Looking forward to reading those useful informative posts on proper procedures and tips for proper installation.

So, now that you know more about what I'm after, let me sum up what I had in mind since the beginning of the post and you tell me where you think I'm off. My 87 has leaks and I don't really know what the overall condition of the system is...ie expansion valve or other parts, but I'm told it works if I fill it with freon or a substitute. I'm going to ignore the part where i say if I want it to work for the short term, I should fill it with duracool and run that until I'm ready to replace the entire system which won't be long. So, when the day comes that I'm ready to replace the entire system, I should replace the compressor (using your installation instructions that you are going to post) , upgrade the condensor with the new more efficient model, since I'm already in the dash, replace the expansion valve and a/c lines that are prone to leak with the new refrigerant. Clean all remaining parts and reassemble. So my kit should include...new compressor, new a/c lines, new condensor and new expansion valve and drier of course. Did I miss any parts that I need in my "kit"? I should then test it for leaks and evaluate the overall system with the proper equipment (again following the guidelines you are going to post) to verify all is working properly. How does that sound to you?

Great question. I "my" opinion I would not use them. Everyone is entitled to their opinion. But, if you used the hyperlinks below the picture you would get a better understanding of the term "flammable" and its use as it is understood by the government at this time.

For instance, gasoline is not flammable in terms of itself, however when presented in a particular ratio with other gases, such as air, it is very "flammable".

This issue of "flammability" and hydrocarbon based refrigerants can go on on. However the powers to be (EPA) established the rule (not me). And if you need to have your ac serviced at a reputable shop someday (and I'm saying you have to) then you could end up hitting a wall. If you can't click on the hyperlinks noted above,
here is the text (again, for the critiques I will reiterate,
I'm just pointing you to the <u>facts</u> that are present at this time; you make up your own mind).

<b> from the site: </b>
http://www.epa.gov/ozone/snap/refrigerants/hc12alng.html#q8

<i><b>
Since the autoignition temperature of HFC-134a is lower than that of hydrocarbon refrigerants such as HC-12a� and DURACOOL 12a�, doesn't that mean that HFC-134a is more flammable than these hydrocarbons? </b>
According to both Underwriters Laboratories and the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE), the main standard-setting body for refrigerants in the U.S., hydrocarbons are flammable materials. <b>Flammability</b>, as defined by the American Society for Testing Materials (ASTM) E-681 standard test procedure for refrigerants, <b>means that a substance will ignite at atmospheric pressure when mixed in some concentration in air at normal temperature and pressure. </b> The minimum and maximum concentrations at which ignition will occur are called the lower and upper flammability limits in air. Hydrocarbons, <u> like the components of HC-12a� and DURACOOL 12a�, become flammable at concentrations as low as 2% by volume. </u> These values are well-established in published literature.

Autoignition temperature is a distinct measure from flammability limits in air. Specifically, this test measures the temperature at which a substance will spontaneously ignite, without any external ignition source like a match or lighter.

<b>Certain documents claim that because the autoignition temperature of HFC-134a is below 750 degrees Celsius (1382 degrees Fahrenheit), it is flammable, and because the autoignition temperature of hydrocarbon refrigerant blends such as HC-12a� is above 750 degrees Celsius, it is nonflammable. </b>However, <b>this statement misrepresents the procedure used by Underwriters Laboratories to classify refrigerants.</b>

<u>UL first examines whether a refrigerant burns in air at some concentration and normal pressure and temperature. If it does ignite under these conditions, it is classified as flammable. </u> <b>Hydrocarbons, like the components of HC-12a� and DURACOOL 12a�, are classified as flammable. </b>(Note that hydrocarbon refrigerant manufacturers recognize that their products are flammable, and label containers for those products with the word "flammable.")

If a refrigerant is not classified as flammable as a result of this test procedure, UL then uses the autoignition temperature to distinguish between practically nonflammable refrigerants (meaning the autoignition temperature is below 750 degrees Celsius) and nonflammable refrigerants (meaning the autoignition temperature is above 750 degrees Celsius). <b>HFC-134a does not ignite, regardless of concentration, at atmospheric temperatures and pressures. </b> This means that at atmospheric pressures and temperatures, if a can of HFC-134a is opened and a lit match is placed in front of the can, the HFC-134a will extinguish the match. HFC-134a is classified by UL as practically nonflammable because its autoignition temperature is below 750 Celsius. Note that UL lists most alternative refrigerants as practically nonflammable. HCFC-22, the refrigerant used in most home air-conditioning, is also classified as practically non-flammable. </i>

Porsche-O-Phile

Would you put on a Sanden or go with a new Kuehl from Griffiths and why? I think it was you that said their products rock so I'm wondering why you wouldn't go with their products.

I'll answer your last comment's question in three parts:

1) Everything you have asked, "nearly" everything that has been discussed in this thread up to this point, has already been discussed either in other PP or Rennlist forums or on certain websites (much by the way we address under a "general" ac help page). What I had liked about the thread was it was drawing in so much comment on so many specific ac issues, whether pro or con (and unfortunately at times with sarcasm rather than critique), and bringing it together under one thread title. I will also add the with respect to forums, when it comes to information, the problem with many forum "formats" perse is that you have to dig and dig to find your answers. But that is the nature of forums. Once again this thread had, and maybe it still does, the potential to gather in one place everything you "wanted to know about the 944 ac system and experiences". <b>Zero10 pointed it out perfectly </b>, give that man a Becks.

2) Our firm does not publish what you are requesting on non-affiliated private sites to the detail you are asking. And, it is my understanding that there is a limitation as to what a particular private site wishes to hear and see in terms of "other's" products. Should the powers to be wish to have you read such a topic, and it fits within our scope of marketing the product or service, then naturally we would do so. However should anyone have a problem with a product, procedure or service of which I can offer an opinion without overstepping a boundary I would be more than happy when time permits to comment on our experience of the subject matter. But I'll be frank with you, I really don't think you want to hear our opinion as you have commented throughout this thread on numerous occassions. But that is OK, I'm from N.J., I can handle anything you got in mind so long as it does not interfere with my golf game.

3) I think if you want to only look at your own needs (with respect to your intial and last question) even though you started the thread, it would be a disservice to this board;
to end it here would make this thread an oxymoron.

So my suggestion to you is to keep the thread going.

Sit back, read and enjoy.

Regards,
Griff
<i> To bring about change you first need a little KAOS.
Want to learn something, try Hören </i>

A Beck's sounds good. Then again, I've never had one. I wonder if I can even get one locally? When I have beer I usually have Keith's (the pride of nova scotia... or something, it's Canadian and it's good, so I don't complain). If you've had Keiths, how does Beck's compare to it?

Sorry to side-track this thread with something so trivial as beer.... It's just so yummy ;)

I like to think I know a lot about A/C. I've read pretty much everything on the Griffiths site, lots of A/C books, and much propaganda from refrigerant-substitute producers....

And yet, this thread has informed me of quite a few things that I did not know. I hope it does not die here. Perhaps the optimal outcome of this could be some kind of A/C troubleshooting/repair guide. I know there are a few out there, but perhaps one could be written expressly for one of the major 944 information libraries, such as Clark's Garage. I'm sure he would be more than appreciative to receive a professionally written detailed guide to A/C on 944's. Perhaps that's taking it a little too far, I don't know.

Zero 10

I agree, keep the thread going.
Here are a few more obvious "helpers" for the newbee on ac work. I pass these along as some clients have brought up situations involving these issues:

1) When loosening or tighten the ac hose line fitting nuts, especially on items such as the condenser or evaporator, always use two wrenches, one to hold the adjacent nut on the component and one to turn the nut on the hose. This will help to avoid twisting (damaging) the tubing on the mating component.

2) When inspecting the site glass on the receiver drier, to determine if there is refrigerant in the system, the system must be operating (engine on, ac on max cold and the outer clutch hub on the compressor is turning).

With R12 refrigerant, if you see a solid and relatively clear stream in the sight glass then "chances" are the system "may" be full. If you see an occasional small bubble go past in the stream, this is acceptable. If you see many bubbles, a string of bubbles or large bubbles then you most likely have a low charge. If you see an oil streak without any signs of refrigerant washing the oil away, you most likely have a very low charge.

With R134a it is not always common to have a solid stream of refrigerant and in many cases the refrigerant stream may appear to be "milky". R134a refrigerant charge levels are best checked using a P&T method (pressures and temperatures), whereby you are examining the high side pressure (using an ac service gauge and hose set) and comparing it to the ambient (outside) air temperature on a chart.

Maybe this would be a good time to hear from owners/users experiences using alternative refrigerants on the topic of determining the charge state of the system?

Or, maybe we can continue the thread with the topic of starting a micro brewery, get a license from P to carry their trademark on the bottle, and then sell some franchises to distribute it.

I had my system fully evacuated and filled with R134a. When it was operating, and the pressures were within spec I saw a very milky stream going by in the receiver/dryer. Some lighter patches went by, maybe bubbles, who knows?...
It worked wonderfully for all of 15 minutes before I had an O-ring on a R134A adapter fitting blow out, and I watched all of the oil and refrigerant pour/spray out of the fitting underneath the car.
So, away we went chasing down leaks. Replaced all O-rings, and re-filled with R134a. This time I got around 3 days of operation out of the system, but after 1 I knew that it was leaking. Low side pressures kept up for quite some time though, and I got a slight cooling effect still after 3 days. At this point the low side pressures started to fall, and I decided to stop using it before I damaged my compressor.
A quick peek underneath tells me that I may have a front seal failure on my compressor. I cleaned it up as best as I can to watch for any new leaks from that area. I also discovered that again the O-ring had failed on my low-side adapter. I tried to remove it and replace it with another one, but the only ones I could find didn't have the valves in them, and my R12 fitting had the valve core removed. So none of the ones I could find would fit.
This caused an oil spray that covered virtually everything down there, and I had no idea what was leaking.
Again, I changed the O-ring, being as careful as humanly possible this time. Now, I had gotten completely tired of paying $140ish to have my system filled with R134a, so I headed over to Auto Value and picked up a couple cans of duracool, and used the low side pressure gauge I had kicking around (from topping up my dad's R134a system in his bonneville). I re-filled with Duracool. They explicitly state not to pull a strong vacuum on the system when using Duracool, but this just doesn't make sense to me, and I did anyways. It took almost 3 cans to fill it, and I had a stupid moment, and checked the low pressure at idle only.
The cooling performance was less than stellar, and in re-reading the posts here and over on Rennlist, I found that I needed to check the pressure at 2000RPM. Had a friend hold it at 2000RPM, and I found my low side pressure was ~15-20psi low. It took the end of the 3rd can before the pressure came up to an acceptable level. From here on it worked absolutely excellent.

Unfortunately, this happiness only lasted about a week before again it was dropping off, and again that O-ring had failed.
However, at this point it was looking like the compressor-evaporator line was leaking, so I will be removing all of the lines to have them repaired (And while I'm at it, have a valve core put back in the R12 valve, and get a straight-through valveless R134A adapter).
I still have no idea if the compressor is leaking.

I thought I would share my A/C story.
Now I guess I have 2 possible choices. Either I can replace the lines and take my chances with the compressor (could be perfectly fine, but the car is from TN, and IIRC it gets pretty warm there....), or buy a nice compressor kit, and only replace the lines that it doesn't include.

Now, there is one thing I should say. I am very hesitant about cutting and splicing A/C lines, and using hose clamps to secure the ends. Is this required with the Griffiths kit, and if it is, how does this hold up in the long run?

As for your 2-wrench tip on the lines. Couldn't have said it better myself. What I always do, is take 2 open-ended wrenches, and set them up so that if I squeeze them together it will loosen the nut on the line. This way it imparts virtually no torque to the system as a whole, and gives me maximum leverage.....

Damn, I'm in physics class right now, I think it's showing!
Now, where did I put that beer..... ;)

Well we got a few moments here while we figure out why turbotubtax updates don't want to update. Let's see if we can respond based on the subjects in the thread:

<b>R134a Charge Port Adapters</b>
these are the little buggers that screw onto the old R12 "schrader" valves (the things that look like tire's valve stem). With R134a refrigerant the service port (the old schrader valve) needs to match the end of the service hose couplings. With R12 you would screw on the service hose coupling. With R134a the coupling "snaps on".

There are two different <i>sizes</i> R134a charge port adapters. The one with the smaller outer diameter is for the the low side (suction) side of the system. The larger outer diameter is for the high side of the system. The adapters are usually supplied with a protective cap. Sometimes the caps are color coded, such as blue for the low side and red for the high side, and sometimes both caps are black. So it is best to examine the outer diameter of the two to determine what should be where.

There are two different <i>styles</i> of R134a charge port adapters.

<u>The first style </u> you simply screw onto the old R12 schrader valve. This first style has a pin inside that will press down on the old schrader valves "valve core pin". When the R134a service hose coupler is attached to the R134a charge port adapter it has a pin inside that will push down on the valve core's pin. By the way, there are two styles of couplers; one that is a quick coupler which immediately presses down once it is seated, and one that has a knob that turns inward or outward to engage the pin; more about that later. The valve core pin is visible inside the old schrader valve. The problem with this first style of adapter, that simply screws onto the old schrader valve, is it sometimes pin does not properly make contact with the valve pin inside the schrader valve. You also may want to consider replacing the the old valve core inside the schrader valve as in time they fail; the typical failure mode is rather simple to fix as the core is simply lose; you can fix that by using a common bicycle valve tool and tighten it up lightly; however if the schrader valve's seal is worn you will need to replace the valve core.

<u>The second style </u> of R134a charge port adapter,
and this happens to my favorite, requires you to remove the old valve core inside the schrader valve. After you remove the valve core you just screw this adapter onto the old schrader valve. The benefit of this style is you are getting a new valve core with the adapter and avoid the problem of the first style's pin alignment.

<u> R134a charge port adapter o-rings </u> depending upon the style of the charge port adapter, it may or may not have an o-ring located inside the section of the adapter that mates up with the schrader valve. Usually the "second style" does. However check with your supplier when you purchase to determine what type you are buying. If the top taper of the old schrader valve is damage or has a "burr" it could tear and damage the adapter's o-ring mentioned above. Put a dab of refrigerant oil on the o-ring prior to installation (as with the replacement of any o-ring when servicing the system). When you screw on the adapter with an o-ring such as this DO NOT over tighten it. What is overtighten? We have installed several hundred of these adapters and frankly I have yet to see a published torque spec., however this what we use "something that is 1/2 of spark plug tight". Though that could sound vague, it works provided the threads are clean on both mating parts and not binding.

My adapters were the second type.
Honestly, I prefer the first type.
The second type adds another O-ring to the system, and from what I have seen, these are the most common points of failure.

The tightness argument is another good one. Like you, I was unable to get any torque specs for these things.... I think my schrader valve is damaged somehow. I have some spare lines from my 86 (one of the rubber sections burst in the fire), that I will probably have rebuilt to work on this car.

Just curious, if I buy the griffiths Kuhl kit, do I need to change the ends of the hoses that go onto the compressor?
The web page is vague. On one page, it states that you get a new high pressure hose and fitting, then on another, it says you will have to splice the low pressure hose, and doesn't mention the high pressure one...

Seems to me, Porsche uses some rather unusual fittings on the compressor, so it would make sense for both to be replaced...

If I brought my hoses and such to a shop to have them rebuilt, they could probably put the right ends on them to fit the compressor, no?

I'm considering the Griffiths kit, with the Kuhl compressor and serpentine condensor for this summer. Working A/C is nice, and if it helps airflow over the rad at all, it's worth it :)

To be fair, I haven't used any of their compressors yet. Heck, maybe I will in lieu of the Sanden if/when my 951's Nippondenso blows up - at least I'll have a basis for direct comparison then.

My comment about the Griffith's stuff is mostly based on what I've heard by other guys who have used their compressors. Their prices aren't bad and they give a lot of very good information on a/c systems and service on their web site. Based on all this, plus testimony of others, their stuff seems top-rate and I'd love to try it out.

To be fair, the comparison of Sanden to 'denso I made is comparing a NEW Sanden unit to a slew of used 'denso units although it should be mentioned that a new 'denso runs in the $1500-ish range whereas a new Sanden can be had for under 500 bucks. Also, be careful (if you do buy a Sanden) which one it is. The particuar one I got was marketed as part of those "134 conversion kits" but is actually an r-12 compressor. Sanden does make "native" r134 compressors (check their web site) which use the same block but have some different internals and seals. As such, I run it as a r-12 (or approved equal, such as Duracool or Freeze-12) compressor. I did run it with actual r-12 with great success for a while until the high-pressure hose blew.

I plan on getting one of the kits for vacc/flush very soon (hot weather going to be coming soon) and replacing my hoses, o-rings, R/D, and probably the condenser & expansion valve. I'll try the 'denso I have sitting around first. If it ****s the bed, I'll re-flush and try one of the Griffith's and report back.

On a slightly different subject, I have had an issue with two later model cars (1988 944 and 1994 968.) When the cabin is warm, I hear a loud and very irritating clicking sound from the passenger side of the cabin. On the techincal board of the PCA website, another owner described this same condition and said it was a vacuum switch. The responder said this was a Nippondenso part and could not be sourced from Porsche. Has anyone else had this issue? If so, what is the fix?