87 911: Replacing dryer and expansion valve and lines. Anything else needs to be rep?
 

87 911: AC question.

Am charging system. All works, it just blows warm air.

Replacing dryer (with Porsche dealer part)and expansion valve (with Porsche dealer part) and all lines (Barrier hose). Anything else needs to be replaced? I will be speaking with the parts counter tomorrow.

Will have condensor and evaporator cleaned and pressure tested too.

Thank you.

Regards,

Are you converting to 134a? I would stick with R12. Just help my brother charge his Miata over the weekend. While we had the equipment out, we also recharge the Ford pickup a/c. Both are blowing COLD air again.

My Porsche is still blowing COLD so decided not to mess with it.

Have the evaporator cleaned before you install the new expansion valve.You will also have to replace some amount of refrigerant oil lossed in the lines and drier you are replacing, my guess would be about 4-5 ounces.Not sure on a 87 but if the fittings are oring style use new orings made for AC.Pull a vacuum for an hour or two,check overnight for leaks and if there are none go ahead and charge.

You might want to have the compressor checked for leaks first as well. Make sure that the electrical side of things is OK, and that the compressor is actually engaging (should be able to hear the "click" with the engine off). Also, before you buy the factory replacement receiver/drier, you might consider going with a more effective/efficient aftermarket unit such as the Pro-cooler.

Here are a few places that you might check or call for more info and advise:

Rennaire /Pro Cooler (rennaire.com): 830-935-3343.
Performance Aire: 714-634-9184.
Arizona Mobile Air (ackits.com): 602-233-0090.



SmileWavy

Ruf- Porsche: was thinking 134. I don't think we have any 12.

Eric: Yes it engages fine. When you say electrical side. Please elaborate.

And lastly, one symptom, I heard once was a LOUD whine under the dash. Once I figured out where the noise eminated from, I turned the switch off, on. I think that since [it] had not been turned on for, say several months last winter, it being off was the problem. With use, should be ok. Will look at it if I hear that sound again (only heard it once).

Thanks again.

Regards,

I would not spend the money on the porsche parts for dryer and expansion valve unless you really want to. The dryer is $35 aftermarket and the expansion valve $25. Save your money for something else.

Oh:

Eric: What about this compressor check part. Does the same company that I would let clean and test condensor and evaporator do this, or do we use the gauges.

Board:What are the numbers on the gauges (high/low)supposed to be?

Rfuest911SC: When you say, "Pull a vacuum for an hour or two,check overnight for leaks and if there are none go ahead and charge.". I was planning on pulling a vacuum for three hours. What do you mean by "check overnight for leaks?

Regards,

Any A/C shop should be able to pressurize the system and check it for leaks. The compressors can leak and/or blow the seals (tell-tale "splatter" on the underside of your decklid?), at which point you will need new seals. the loud whine under dash sounds like your evap or fresh-air motor going TU. When I mentioned checking the electrical bits that's basically what I was referring to: Check that the electrical connection to the compressor is good, and that the compressor clutch actually kicks on. Also, check the (evap) blower motor/fan, front condenser motor/fan, and a/c relays.

I haven't started this project and have not seen the front condensor blower fan yet. Locating it will be next, then finish my plan an on to removing parts, cleaning checking/ replacing reinstalling them. The evaporator could have made that noise, hmm. I thought it was in the smugglers box (I have to go there next too. I know it is hard being at two places at one time :) ). How do I check the blower(s)/fan motors(s)? Oh my lord. You said relays, ouch. Where are they (how many) and how do I check them. I learned a long time ago how not to hurt my cars electrical/electronic parts. I won't do anything I shouldn't.

Until this is all sorted, I have to rely on the Targa top being removed. I just had a vision. My cold AC blowing out as the top is usually going to be off.

DonMo:
Where should I go to get those. Given those prices you state, the dealer may be closer to $400 plus, and I tend to agree with going with an outside source for AC parts.

Where do the o-rings go, What size are they?

Regards,

Re: 87 911: Replacing dryer and expansion valve and lines. Anything else needs to be
 

Here are my thoughts:

Since you're replacing the hoses, I'd stick with R12. In most situations, it will blow colder than R134.

DO NOT go to the Porsche dealer for the receiver/dryer and expansion valve. Consider adding a ProCooler in place of the receiver/drier. Also, since you'll have the system apart, you should also consider replacing the evaporator and expansion valve with the Rennaire product. www.rennaire.com. Ron Maxwell owns ProCooler and Rennaire, and he knows his stuff. If you're not going to add a ProCooler, then there are aftermarket receiver/driers for a fraction of the cost of the factory unit that will work just fine.

I'm assuming you're having the hoses made up locally. If so, the vendor will have all the O rings you'll need. Get one for each fitting, and get extras.

If you're not having the hoses made up locally, take a look at the Rennaire kit. $369 for everything. It's a good deal! (And, I have no interest in Rennaire. I just think Ron puts out a good product at a reasonable price.)

Take a look at the underside of your rear deck lid, near the compressor. Is there a spray of dirt and oil there? If so, the seal on the compressor may be shot. Compressor Interenational in Van Nuys, California has good prices on rebuilt units. You can also get the seals from www.ackits.com if you feel like you can handle a DIY job.

Add the factory fuse harness to the front condenser fan. It will prevent a fire. Pelican sells the part. IIRC, it's about $30.

There are all sorts of other things you can do, but this is a good start! Have fun. Be safe.

Deck lid is spotless. I have always kept it clean, but not sure. I would know if it had that problem. I have seen that problem before so I know what it looks like.

That nasty evaporator huh. How do I ascertain that it is intact (or otherwise) inside? How about the shop that I take it to. Can they tell for certain, if it is good.

Off to find R12.

Regards,

They can clean it out and pressure test it. The Rennaire unit is reported to be more efficient, thereby providing greating cooling capacity.

another alternative to r-12, which is 'just as cold', compatible with r-12 and legal is freeze 12 shown below:
ryan

ANSWERS TO COMMONLY ASKED QUESTIONS ABOUT FREEZE 12®

What is the EPA status of Freeze 12 ? Freeze 12 is EPA acceptable subject to use conditions for mobile vehicle air conditioning.
Are Freeze 12 and Freezone the same? The two are similar in formulation, but are two different products. TCC only markets Freeze 12.
Is Freeze 12 military approved or approved by TARDAC or MEEP? No, it is not.
How much will Freeze 12 cost? It will be priced less than R-12 was in 1995.
What is involved in a retrofit to Freeze 12 ? The law requires that the existing refrigerant in the system be evacuated and unique fittings and a label be installed with any replacement refrigerant. Also, if the A/C system being converted is equipped with a High Pressure Relief Valve, a High Pressure Cutout Switch must be installed in accordance with EPA SNAP regulations. Use of Freeze 12 does not require that the lubricant or other components be changed.
What are the requirements for recovery equipment with Freeze 12 ? The EPA requires that recovery of Freeze 12 must be done with a dedicated recovery unit. TCC offers a competitively priced unit for this purpose.
If Freeze 12 is recovered out of a system what should be done with it? TCC has a return cylinder program for the recovered material to be sent back to us.
What is the warranty of a new compressor using Freeze 12 ? At this time some evaluations are taking place which will determine the warranty situation of a new compressor using Freeze 12. Currently there are no new compressor warranty endorsements for Freeze 12. We expect this to change as there were no new compressor warranties in the beginning for R-134a retrofits and now most compressor manufacturers offer them.
Why should I retrofit an R-12 system with Freeze 12 instead of R-134a?
1. Freeze 12 will cool better than R- 13 4a in most retrofit applications.

2. Freeze has a pressure curve which is close to R-12 while R-134a operates at significantly higher pressures than R- 12.

3. Freeze 12 works with the existing mineral oil and does not require lubricant replacement as R-134a does.

Why should I buy Freeze 12 instead of one of the other alternatives?
1. Freeze 12 will be competitively priced compared to the competition.

2. Freeze 12 has been thoroughly tested and shown to be an effective replacement for R- 12.

3. Freeze 12 is expected to have excellent distribution nationwide to insure that it is available for the consumers car wherever they may need service.

4. TCC has been in the refrigerant business for over 30 years with the expertise
and knowledge to provide this product to the marketplace.

Can I use Freeze 12 in non-automotive applications?
Because of the license agreement on this patented product, TCC can only sell it for automotive use. TCC is Technical Chemical Co. and is the manufacturer of Johnsen Products/Freeze 12.

btw, i paid $24/lb for it last week and have been chillin' ever since..
ryan

It sounds like you are going to pull a vacuum yourself,if that is true I am assuming you have a set of AC manifold gauges,if that is true that's how you check overnight for leaks.You pull a vacuum and the gauge will show aprox. negative 29 inches of vacuum,you close all the valves and disconnect the vacuum pump and let it sit overnight. In the morning you check the gauge,if it satayed at the setting then you have no leaks,if it changed you have a leak/leaks. I agree with the others buy your parts from aftermarket suppliers they are much cheaper and work just fine. I used ACKITS.COM.

I bought my dryer and expansion valve at the local ac supply house, they usually don't sell to the public but if you work for a large company, they will usually sell to you under their name as long as you pay cash or charge. As an option, www.ackits.com will sell you the parts much cheaper than Porsche.

What do you use to pull a vacum?

rob,
you use a vacuum pump.
ryan

A lot of good advise here. Do a search on "Jim Sims" and you'll find lots of great advise, he is the A/C God around here. Jim recommends against most of the alternatives to R-12 and R134a because according to him the others don't pick up the refrigerant oil to lube the compressor and it prematurely fails. The O-rings go on the hose ends on your car, make sure there are made for R134a if that's what you use (green I believe). While it may work, think twice about handling flammable compressed gases such as Freeze 12 and the other propane/isobutane substitutes (nothing like compressed flammable gases next to your face while the engine is running).

Good advise above, you should know that most shops do not like anything but R12 and R134a, their equipment is at risk when they remove your "strange brew" into their recovery systems. That being said, if you are a committed DIY kind of guy and don't plan on ever using a shop, have at it.

hugh and others who may not have researched freeze12 and other potential substitute refrigerants, read a page from the epa regarding use and conditions for use of alternatives..this includes a table below of 'acceptable and 'non-acceptable'. fwiw, freeze12 is 80% r-134a & 20% r-142b (zero isobutane/propane blends) per the epa link below. also, freeze12 is advertised as non-flammable..visit www.freeze12.com for more info. duracool, another product mentioned often on this board, is listed as an 'unacceptable' replacement, just for an additional data point. although my 'research' of this info is purely online, a degree in chemistry does allow me to read and understand msds info.
ryan

http://www.epa.gov/docs/spdpublc/snap/refrigerants/macssubs.html

Is the receiver dryer under pressure when the A/C is not on? If I remove the current receiver dryer to replace it with a new unit, will I lose refrigerant?

I am taking my 86 coupe in for A/C service next week and would like to test fit the new receiver dryer before then so I can ensure that I have the correct part.

Many thanks as always.

Mike

Yes. Once you crack one of the fittings, you'll allow refrigerant to escape and air and moisture into the system. The better, and more environmentally friendly, way to go is to have your local a/c shop recover the refrigerant. Then you can work on the system before having it recharged. Use care when exposing the new receiver/drier fittings to the environment -- there's a desicant in there, and if you allow it to be exposed too long to the elements, it will absorb moisture and not be as effective.

Good luck. Have fun. Be safe.

I looked at the MSDS and Freeze-12 is 75-90% 134a, and 10-25% of some other CFC. Compared to hydrocarbon coolants, it should not be nearly as flammable. My only complaint with it is that it still has a CFC in there.

http://www.freeze12.com/pdf/6030.pdf

Actually, 142a is an HCFC (CH3CClF2) the same class as 134a - and it's not considered flammable.

You guys with a large enough compressor can pick up a vacume
pump at harbor freight for about $15.00. Use it in conjunction with a set of a/c gauges and you are there.

Keith Epperly
87 slant nose turbo look carrera cabriolet

I use the (Ken) venturi vacuum pump. Works for me.

Brian

Another tip, go to your local a/c supply co. and ask for some "fin" clean. While you are there get a fin comb also. The front condensor fan is in the left front of the trunk. You can take it out and disassemble and relube the motor's bearing and reinstall.

Keith Epperly
87 slant nose turbo look carrera cabriolet

"You guys with a large enough compressor can pick up a vacume
pump at harbor freight for about $15.00. Use it in conjunction with a set of a/c gauges and you are there."

Nope; these venturi pumps can't achieve a low enough pressure (enough vacuum) to get the water out. This is especially bad with the R-12 systems, for water and the R-12 refrigerant combine to make an acid that corrodes the systems from the inside.

CORRECTION 142b IS considered flammable

I've already mentioned this several times on the board but if you live near an Autozone you can borrow a vacuum pump for FREE via their loaner tool program. They have a pretty decent electric pump and is yours for the asking and a $200.00 fully refundable deposit. Just make sure you buy fresh oil for the pump as you can bet what's in the loaner needs to be replaced.

I looked in the Pelican Parts catalog but couldn't find the front condensor fuse kit that scottb mentions. Can anyone direct me to it, or give me more information about it? thanks

Jim Sims. BS I let mine run for 30 min. and achieved -30psi.
For the fifteen bucks thats a bargain, I have a 7.5 hp 220 volt 60 gal. upright compressor. I replaced the receiver dryer pulled a vacuum, recharged with r-12 and that was two years ago still running 38 degrees at outlet on a 90 degree humid day. Don't forget to take a valve stem tool and tighten the schrader valve most shops COUNT on seeing you once a year for a top off as a residual and leave the valve 1/2 to 3/4 loose to allow for a Small leak. And don't forget to run the a/c during the off months.

Keith Epperly
87 slant nose turbo look carrera cabriolet

kepperly,

-30psi? Now that's BS or you're in a very deep hole in Kansas. Wait, the Kansas State School Board considers things magical there so maybe it's possible.

I assume you mean 30 inches of mercury of vacuum which of course is also impossible at the elevation of Kansas; atmospheric pressure isn't that high there. Vacuum in inches of mercury is read relative to local atmospheric pressure. You cannot use your Bourdon tube based harness gages to accurately read vacuum.

You have to get the pressure of the system below the boiling point of water at the system temperature for an extended amount of time to mobilize the water and pump it out the 40 feet of hose (in a 911 AC system) which has poor conductance for vacuum pumping.

Here are a few values at sea level:

vac (inches of mercury): 28.89 water boils at 80F

vac 29.18, 70F

vac 29.71, 40F

vac 20.86, 10F

This is at sea level, reduce the vacuum levels required for a given water boiling point by an inch of mercury for every 1000 ft of elevation above sea level.

Put the car in the sun, pump down to 40 microns (this requires a two-stage vacuum pump with dry (fresh) vacuum pump oil) and let the pump run for 3 hours.