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740 R12 vs R134 parts?

M

Magnanimous

Member
Joined
Dec 21, 2015
I'm in need of a new AC compressor for my '87 740. From what I can tell, it appears that the previous owner did an r134 conversion. I'm not looking to deal with the hassle of r12, myself, but as I'm looking for replacement parts, do I need to look for parts from newer cars designed with r134 in mind? Or will I be able to use r134 with the standard 1987 compressor component kit?
 
I purchased a compressor for my 240, it came setup for 134a. Even if it came setup for r12 all you have to do it drain the oil and refill with 134a oil. But seriously doubt it will come with r12 oil. If I remember right mine came with a tag stating what kind of oil was installed. Duracool has a smoking deal on brand new compressors right now.
 
There is a difference using R134a vs R12. The R134a raises the head pressure putting more strain on the system. So if you had a compressor that had been running r12 and you convert it to R134a can help the compressor to fail sooner. R134a is a poorer refrigerant. It doesn't run as cold. You can change/adjust the pressure cycling switch to help.....but it will never be as good as running with R12. All the parts of the system including the compressor will be the same for R134a.

MAB
 
It depends on what the extent of the conversion is. A lot of people will just screw a daggone adapter onto their R12 system and boom. Converted.

I'd grab the part numbers off of the compressor and see if it's the stock R12 or an R134 version. Then get that.
 
no volvos are not listed but Im sure you can find a cross reference but I could be wrong. I dont believe that volvo compressor just fits volvo. But I have been wrong before I will do a little digging myself and let you know what I find out. Worse case call them and ask.
 
hexibot43 said:
There is a difference using R134a vs R12. The R134a raises the head pressure putting more strain on the system. So if you had a compressor that had been running r12 and you convert it to R134a can help the compressor to fail sooner. R134a is a poorer refrigerant. It doesn't run as cold. You can change/adjust the pressure cycling switch to help.....but it will never be as good as running with R12. All the parts of the system including the compressor will be the same for R134a.

MAB
Click to expand...

I stand corrected. You will use PAG oil instead of the ester oil that would have come with R12.
 
I had to replace my a/c and flush out all the lines and the condenser with pressurized a/c cleaner. So I decided to switch to 134a for simplicity sake. It is very cold I doubt you could tell a difference. Another option if you don't want to convert is propane just don't tell anyone.
 
1234yf is a straight replacement for 134a. You don't have to change a single thing with current 134a cars to run it and it's the same efficiency just not as much of a greenhouse gas. If you were so inclined you could drain all of the 1234yf out of it and put 134a in and the system would function properly.
 
envirosafe or duracool both are cheap options and keep the car hella cool
 
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