a/c questions
 

I took my 83 944 into the shop today for a/c work after getting sick of sweating bullets in the humid 95 degree East Texas weather.

My a/c has been blowing hot air and the shop told me that my evaporator to compressor hose is leaking and must be replaced. The shop claims they might be able to fabricate their own hose, which would save me money. Tweeks sells these hoses for $299. I can't find prices from any other vendor.

Of course my a/c will have to be recharged. My a/c was last recharged with R12 back in 1999. I was told it had a leak but I choose not to have it fixed and it held charge for 3 years.

I know this is going to be very a $labor$ intensive job.

Questions:
1. Should I replace the condensor to evaporator hose with fabricated unit?
2. Should I recharge with R12 or R134a?
3. What do you think this will cost me considering all the work will be done by the shop?

Thanks for any input.

Don't be afraid to allow them to make the hose, I had one made for about $25 bucks a few years ago, it still looks new.

Converting to R134a will allow you to add refirgerant the next its low for a few bucks a can.

My opinion...

Convert to R134 just because it is cheaper to recharge (DIY) and it is theoretically safer for the environment. Problem is that R134 reportedly does not work well with our AC system. Talking to the guys at Zims (in TX), 100 deg ambient temps produce 70 deg AC air with the R134. In Brunswick ME that is not a problem, in Texas it might be a problem.

What little experience I have with auto A/C and with what I've read about our OEM compressors, I would seriously suggest change the compressor to a Sanden or Kuehl if you do go to 134. The higher operating pressure for the 134 will blow the seals on the OEM compressor.

According to the Tech Directive from Porsche, if you do the 134 conversion, the only components that must be replaced are the charging ports, o-rings and receiver/dryer. I am going to replace the expansion valve ($30) so I can do a thorough flush on my system.

If you get them to make you a new hose, make sure it is guaranteed. $200 labor twice for installing a $25 hose twice is not worth it.

Dave

I'm out here in Ft. Worth. My 951 has been converted over to R134a but I hear the earlier (pre 85.5) cars didn't have the same capacity. So far, it has been working pretty well but it isn't as hot here as it is going to get!

You might consider alternate refrigerants such as Duracool. Check this out www.duracool.com. I've used it for 6 years in one car and for 4 years in another.

Thanks for all the suggestions. 134a with a guaranteed hose will be my course of action.

I'll keep you all updated about the repair.

OK just so we can get an I told you so going here, I would take Lawrence's suggestion. To really get the AC to work right with R134a the system would need some serious ($) modifications. I believe that the newer cars can get away with the swap because of the additional capacity, but from everything I've heard the earlier systems just aren't up to it. There are several R-12 replacements that are cost effective and more efficient (which you need) than the R134a -- you've been warned!

I've been warned and now I'm worried.

I'm not going to rule out upgrading the compressor.

Is there any early 944 owners out there who converted to R134a without upgrading their compressor? Is there a noticeable difference in the a/c cooling.....especially those living in hotter climates.

Just out of morbid curiosity, what is the adversion to going with a R-12 substitute -- I think you still have to convert the fittings over to R134a, but I don't think that this is an expensive proposition, and the efficiency is much higher. The folks at the website Lawrence gave you said that their replacement was even more efficient than regular r-12.

Even though mine is working OK (note I'm also in TX), I was thinking of going back to the R-12 substitute myself for increased cooling and I already have a late model car. As you know! in TX it's all about staying cool in the summer!!! I'm interested to see how well my R134a conversion works down here in the 'heat of the battle'.

The shop my car is at is pushing the R134a. I didn't see any prices for the R12 substitute and I also wonder about the cost/time of ordering it from Canada.

I'll do some more research.

**correction** I see I can order duracool from tenn.

Anybody know where we can buy alternative refrigerants like Duracool?

http://www.duracoolusa.com/

http://www.autocool-refrigerants.com/

Converted my system to R-134A last week. - Charged it completely and have had no problems whatsoever.

Vent temps now running in the 40 - 45 degree range.

AFJuvat

Fox Tool Company in Nashville, TN sells the Duracool. It's about 6 bucks per 6 ounces. You use about 1/2 as much. I usually buy a case at a time for $72.

Thanks. I'm going to try it out.

ac question
 

Does anyone have a contact for diy gas in europe pref Spain or UK Thanks in advance Steve Eliott

Hi,

I was following this post in the past with an interest. I have hot A/C on my car. I read the Duracool thing and was ready to order the stuffs. Just I was about to order, I thought I should ask a few questions to a mechanic who operates helicopter shop next door. He has all the equipments to do A/C work on cars to airplanes to helicopters.
He was not too hot about the Duracool. He says it is not readly available around here. Also it requires some modification to the system, he says.
So is he saying the truth? I would like to know. I would like to hear from someone who is using Duracool.

Maachan

see Lawrence's post above, 4 years in one car and 6 in another. I think all you do is change out (or get adapters for) the fittings (input) to the R134a versions (you'd have to do that for the R143a conversion anyway). I think you should probably put in a new dryer as well -- they are not too expensive

Any input from Lawrence?

Maachan

Been at Road Atlanta track event. Just getting to reading lists now.

In 1996 my 1980 450SL began leaking slightly. Because R12 became unavailable I started searching around. I bought Duracool and charged it without changing anything. It has worked fine ever since. It takes one can a year. The R12 eventually leaked out. The SL is my daily driver.

Two years later I put it in my 944T. It worked fine there as well. The 944 was originally a R12 system also. Last summer my AC clutch began popping fuses. I replaced clutch with a rebuilt one. System worked well for another few months but then AC compressor main seal began leaking. My feeling is that it was a coincidence or it didn't like the tapping on the clutch to get it positioned. I doubt the Duracool had anything to do with the failure of the seal.

I have never tried it in a 134 system so I cannot speak to that. But no modifications are needed with an R12 system.

I do know that if you overcharge the system, it will not work properly.

I have not gotten around to the seal on the 944 yet because I have another car apart at the moment.

Duracool
 

Duracool is a mixture of methane and propane - no wonder it's cheap. It probably costs them a few cents to make a $5 can. Very flammible. If you were in an accident and the system leaked you would have a blow torch!

ain't gonna happen -- first the probabillity that you break a hose is very low (what accident have you survived in which the AC lines were ruptured?), second, if the hose did break you'd have to have either the presence of a spark in just the right place or an open flame. Lastly, the ammount that is in the system wouldn't burn long. There is no rational safety issues in using this in your AC system (IMO).

They claim it is more refined (I kind of doubt that) but it does come in a can that is condusive to filling your AC system and that is worth something -- and it is certainly much cheaper than R-12 and more efficient than R143a.

I have had two accidents over the past 30 years where the A/C ruptured - the A/C coil is right up front! There are plenty of ignition sources - old spark plug wires, electrical short due to the accident. A couple of pounds of gas is not insignificant. Imagine a 2-1/2 lb fire extingusher full of propane. You could broil some great steaks!

You only use about 55-60% by weight. So you only have about 1.25 lbs in system. 944 system uses 2.2 lbs of R-12, I believe.

If the system breaks in the dashboard and leaks there, it would obviously have broken at the front of the car where the system pressure is a lot higher. More gas would exit where the pressure is higher. Moreover, if your accident is so severe that things in your dashboard are being torn apart, you're in deep do-do by then anyway.

You put your money on the table, roll the dice, and take your chances. If you want to be perfectly safe, don't leave your home and be careful getting in and out of the bathtub.

You must be unlucky. I've been in some doozies and never seen it (actually until you said it happened to you, I had never even heard of it happening -- though I figured it was theoretically possible). Part of the reason I think it is remote is the ductillity of the alloys used for the AC system -- seems like the percent of elongation is high resulting in large non-linear behaivior before rupture.

I would put it in without hesitation. So what if it flames -- like you said the coil is up front, away from the driver. Also, I still believe that the chances are remote.

Just because you're paranoid doesn't mean everybody isn't out to get you. If it were that haszardous it wouldn't be allowed in the car. Gasoline is very flamable -- I got a whole tank of that -- I don't worry about that either and my name ain't even Alfred E. Neuman. You are right a couple of pounds of propane are not insignificant; but, less significant than 20 gallons of gas.

I'm much more worried that an SUV will run over the top of me 'cause I'm looking eye-to-eye with his hubcaps.

Life is full of risks both great and small -- I just think this aint a big one -- and I don't even use the stuff as yet. (IMO)

Kenny - get back to your finite element models.

And watch out at Home Depot they have propane powered forklifts and a pallet might fall and cause one to explode just as you walk by. I think I'll go home now - but wait! a gas line might explode! I might stick my finger in a socket! get me to an inert gas filled rubber sphere!!:p

All right already...
 

Okay I hear ya! Life is the management of risks... I agree the propane adds only a small additional risk. However, buyers of this product should be aware of it's flammability so they can decide for themselves. The manufacturer's web site dodges the issue with selective, if not misleading, wording.

Agreed, life is risk management and I like to have all the facts to make the decisions. Thanks, dmac, for the info. The problem I see is that we are to fill a system with a highly volatile substance (granted R-12 is flammable but not nearly as volatile) that was not designed for it. Also, gasoline is not pressurized and there is no safer alternative for it. Is Duracool safe...probably due to the high probablilty of a lawsuit is it weren't. Do I like BS, misleading advertising...nope.

And, oh by the way, a few years ago a pallet did fall and kill somebody at Home Depot (or one of those warehouse) stores, but not by a propane explosion. Right back a'cha, James Adams. I'm all about sarcasm. :D

Wow, in a short period of time there are a lot of input those are very, very good.

As for Lawrence's compressor clutch, it does not like tapping at all. We had to replace one of those on an airplane one time. A mechanic tapped it in ever so lightly. It leaked freon in short time, couples of week, if I remember correctly. We replaced it with help from the guy in next hanger. He brought in all the goody toys, tools. And the job was done.

For this time around, I think I will charge mine with R-12, the guy next hanger has it. He thinks unless there is problem with the system to leak, it is cheaper for me.

I have a question to Lawrence. When you charged the system with Duracool, did you use the sight glass as your gauge? I think I read it somewhere that you should not charge Duracool as much as R-12 would appear in the sight glass. Did you use thermometer at the vent to find if you have sufficient charge?

Maachan

You should always use a manifold set when charging your AC. Regardless of your "Freon" choice you should never exceed certain pressures. That is of course unless you’re interested in failed seals, and compressor replacement. Get a set or borrow a set, and do the job right. I have a 134A conversion that I did that blows just as cold as the original R12 charge. $4 a can when done right is a cheap alternative. I am certified in A/C repair from GM and the EPA. And I can honestly tell you there is no real advantage in going with propane. There are plenty of other alternative refrigerants that work just as well without the added risk. Propane charging in my opinion is the "hillbilly" method to AC repair.

Also, James: There is something to be said for accepting risks in everyday life, but why would you want to willingly increase your risk? I guess I just don't live dangerously anymore....

Don't go by sight glass as you could with R-12. Instructions say that you will over charge if you do that.

Instead, you can begin charging system with engine at 2K. Put a thermometer in duct inside cabin with blower set to 3 or 4. Thermostat should be as low as it goes. Charge until the duct air temperature just passes its minimum temperature and begins to rise. Be sure the rise is not due to cycling of compressor.

Or, charge with gauges until low side of compressor reads about 25-30 psig with compressor running in steady state mode. This is how I do it. The pressure reading is taken with the valve on the can in 'off' position. Otherwise, you're reading can pressure.

Maachan:

"As for Lawrence's compressor clutch, it does not like tapping at all. We had to replace one of those on an airplane one time. A mechanic tapped it in ever so lightly. It leaked freon in short time, couples of week, if I remember correctly. We replaced it with help from the guy in next hanger. He brought in all the goody toys, tools. And the job was done."

This is exactly what mine did. It began leaking in a short time. The compressor seal is my next project unless something more serious breaks.

I'm getting the impression I need some sort of special tool to get the clutch pressed onto the shaft. Tapping, even with a new seal, will cause it leaks? Guess I could take compressor to AC shop. What did you guys do? Thanks.

I didn't, I went to R134a...

Sorry for the late update, I've been busy.......

I got my car back last week and I am running R134a. So far I'm really impressed with how cold the a/c blows.

Now when I turn off the a/c, I hear a whistling/blowing (*chhhhhhhhhhh*) sound that doesn't go away. Any ideas as to what could be causing that?

Thank for everyones input.

To: Lawrence

Hi,
Sorry but I was not in the team those changed the clutch at that time, and I cannot say what had been done on it. All I remember is what I said on earlier post. If the guy is working tomorrw I can ask him in detail.
I had him worked on my P-car's A/C system the other day. He checked the charge of my system as to what is in the system. R-12 or R-134a, any air, contaminants and the like. Luckly there was no air, no moisture, no contaminants and was with straight R-12. He charged 1 pound and quarter of that along with dye and some oil. He said I owe him $100 for the gas. Ouch... He was saying I can pay anytime I want, meaning I don't have to pay???
Well I didn't like oweing anything to anybody, so I paid on the spot.
He is saying do not go with alternative refregerant. If I was to convert, he recomend to go to R-134a. As for me I want try Duracool.

Maachan