Hello all, I recently bought a rebuilt a/c compressor and it has a sticker on it that sais use only PAG oil and it also sais 134a. Another important note is that it has a big sticker on the bag it came in that sais Compressor contains NO oil. My intention is to use R12 because after searching and reading I have found that these systems do better with R12. I have taken all of the a/c components off of the car one by one and flushed them and replaced all of the o rings. So there will be no contamination. Also replaced all of the suggested parts ie.. Drier, expansion valve and compressor. Is there any reason that I can't go ahead and use the mineral oil and R12 with the new compressor even though it has the previously mentioned stickers on it? It is looks exactly like the compressor that came off of the car which of course is R12. Thanks in advance for any info.

 

r12 is being phased out because it is alleged to damage the ozone layer. r134 is its replacement. Older systems that originally had r12 are commonly converted to r134.

I don't think r12 is available anymore

 

Use ester oil. With that you can use r12, 134a, or 152a. IDK if that will void your warranty with the compressor, you'd have to check with the vendor. It shouldn't.

 

I've been using r152a. Compatible with pag oil. Runs cooler than r134a. Although if you choose to use pag oil, you need to thoroughly flush and clean everything else in the system, because it originally had mineral oil in it. Pag and mineral oil do bad things when they mix. Clogs stuff, I believe. I use ester oil. It can mix with either with no trouble (I believe)

There's a great thread in the archive about converting to r152a. Even if you don't convert, it's a great read and will teach you most of what you'll need to get your system up and running.

 

++++1 on ^^^^

Use the ester oil and the 152a if you can or 134a. R12 will be very expensive to obtain and may
not be available later if you have an issue.

The 152a works a lot better than the 134a. I replaced the wifes BMW compressor last year and
refilled with the DustOff cans (152a) and it works better than when it was new. Has lasted now
for over a year and is working flawlessly this summer as well.

Oh and if you go with either 134 or 152a you have to get new hoses made. The old hoses will
leak the smaller molecules of the non-R12 gases. Also new hose is a good idea anyway.

 

Hope you don't mind if I ask a compressor related question on the thread you started Modified85 but the title may attract someone that has an answer for me..........
My 79 SA didn't come with A/C but I have installed all the components from another 79. My car has a 20 amp compressor fuse in the fuse panel next to the hood release but I cannot find any spare wires under the hood near the A/C compressor to plug it into? It was not hooked up in the car I took the parts from either? If someone could tell me where it should be or take a photo of it, it would really help.

Thanks

 

R12 is available at many mom and pop shops. Cash only lol

 

Can any of you guys tell me where the thermostatic expansion valve (TEV) is located. I have a 1985 GS with dealer installed AC. I am hoping that removal of the dash is not required to replace the TEV.

Thanks, any help would be greatly appreciated

 

The expansion valve is located inside the evaporator box. The evaporator box is located just below the dash on the passenger side. You don't have to remove the dash to remove the evaporator box. Its awkward to work on it up under the dash but it definitely can be done.

 

Thanks for getting back to me so quickly.

The evaporator box, would that be the black box located just to the left of the blower on the passenger's side?

One more question, could a bad TEV contribute to the failure of a compressor?

Thanks -

 

Yes, on the left of the blower. I have always removed the glovebox first. Disconnect both lines under the hood at the firewall (and plug them with something). From under the dash, one nut holding the evap box to the firewall on top and one or 2 on bottom. Then the clamps on the ducting on each side.

I'm no expert but I don't think a bad TXV would break the compressor. Possibly if the TXV failed or was plugged with ice and the compressor still ran an extended time. From what I have read, it's the opposite. The compressor fails and debris from the failure go through the system.

 

Thanks

 

For what its worth, one thing I've been told when switching from R12 to either 134a or 152a is getting a little bigger condenser would help make the whole set up more efficient. I have yet to find this out though as AC is still on my list of things to do

 

By the way I found someone close to home that has a 79 with A/C and I was able to see what the wiring harness looks like. That answers my question I asked earlier in this thread...................
The thermal expansion valve is located inside the black box behind the glove box. The system should be evacuated properly before you start taking things apart. You should change all the components if the system failed, the contaminates travel throughout the system and could damage a new compressor prematurely. You should also make sure to replace all the limit or cycling switches to protect the system in the future while you have it apart.
The components are sized and designed to match each other so adding different condensers may not function efficiently. IMO................

 

Great, thanks for the information.

I am going to rely on the AC shop to diagnos what's wrong and what needs to be replaced. However, where is the limit switch located on an 85 GS?

Does anyone have a line on reliable compressors? My car uses the Sanden 9165 compressor, which is only available as a reman. Is there a plug and play substitute or does one just have to cross fingers, hope for the best, and use a reman?

 

Again, that's what I was told by a dude whose been working on rotaries longer than I've been alive. He gave me a lot more detail that I wish I could remember as far as which one to get and why. It came down to the refrigerants just being different and the system being designed/sized for r12 and not having enough condenser for the 134a to fully cool the car, if I remember correctly.

 

Very good info except the last part about the condenser. A larger and different style, more efficient condenser will get rid of more heat only require a little more refrigerant. The stock condenser may be engineered for the btu necessary(w/r-12) but the install is flawed in that air can easily go around it, not through it, especially at idle. Not that a big deal for most of the country but in the south, more efficient heat rejection is necessary, for most people (If you sleep cuddled up next to your mate under the covers at 78°+ then maybe not).
A simple solution is to put a small pusher fan in front of the condenser wired with a manual switch+relay that only operates when the AC is on. Or you can get more elaborate with a thermostatic switch on the condenser. A lot of newer cars come from the factory with pusher fan/s for the AC.
A larger condenser that fills the radiator support so air can't bypass it is more efficient for hot climates.
Good choice with the AC shop, there's a lot to learn for a quick fix doing it yourself with no experience.
The Hi/lo limit switch is usually located at the receiver/drier (cylinder in line at front by condenser) or on the small line just before the firewall. I put a photo of a couple in the other recent AC thread. I'm not familiar with that compressor #, sanden 508 or 575 is common on 1st gens. You can try ACKITS.com Automotive Air Conditioning Parts & Equipment. for a new one. From what I've read, new is much better.

 

I will agree about the condenser and fan Steven. I’m in the process of installing a system in my 79 that I took from my parts car. It didn’t have everything though. I bought an electric fan that I plan on mounting on the front side of the condenser and having it come on as soon as the A/C switch is on through a relay. I noticed my temp gauge started to run about half to three quarters while driving down the highway on a hot day, too high for me. While I was installing the condenser I flushed out my rad but I don’t think I was able to get all the crap out so I bought an aluminum three pass rad, hopefully it will run a bit cooler afterwards. You folks down south must see these high temps fairly often?
If you have a professional look at your system they can check to see if all the components are working properly. Then if they have to open the system they can check the oil in the compressor for acidity or contaminates. That will determine what you will have to change. Your compressor may be fine.

 

Thanks for the information. I located the Hi/Lo limit switch, it's on the receiver/drier. Contacted ACKITS regarding the compressor, unfortunately, they do not have any new compressors for an 85 RX, just remans.

Unfortunatley my compressor is bad, the main shaft seal failed.

 

Unless there's something else wrong with your compressor you can replace the shaft seal. It takes a couple special tools though. The seal is around $25. If you ordered the seal a good shop may install it for you.