Which of these compressors will work with R134a?

[ELVA164]

Hi guys,

Sorry in advance if this is answered somewhere on here; I just finished a trip back from Mid Ohio and I'm frantically trying to organize everything to complete my r134a conversion in the next day or two.

These are the compressors I have.

This is the best picture of the one on my car. It's a Denso, but it's more of a Deadso if you catch my drift.


I bought this one from Wschnitz a while ago. I believe it's the same as the one on my car, but that doesn't mean it's necessarily r134a compatible.


This one came with the car, but I forgot I had it. It's a Sanden, which I believe are all compatible with r134a? It had a bracket with it which I think I remember hearing is different from other compressors'. Also, will the lines from the Denso attach to this one without any issues?


Thanks guys, I'm really looking forward to getting this straightened out and getting A/C for the first time!

[Navarone]

Hey fwend. I was just looking for this answer too because it's been like 90° the last few days.

Here. http://www.r3vlimited.com/board/showthread.php?t=246743

Woops, reread that and it doesn't have the part numbers I saw. Here's a PDF with the part numbers.

http://www.exx.se/techinfo/docs/r134a_retrofit.pdf

[Ryann]

A compressor is a compressor. What makes them 'compatible' is the oil that's in them. R-12 systems used a mineral based oil while 134 systems use POE. That being said.. for everyone's information, after years of research and testing Copeland recently released a bulletin certifying alkylbenzine oils for use in 134a systems.

[Navarone]

Those model numbers are pretty confusing, but from my light reading it seems that the denso 10p15e compressor will most likely work with r-134a as is and for sure if you replace the seals inside and on the connectors. There are rebuild kits for them and they should have green "HNBR" seals.

[Gordo0208]

They're both R12 compressors, either way they should work. I've been running R134 in my original 86 compressor for since I've owned it. I believe it's the Denso model. For the conversion the dealer would perform you need compressor p/n 64 52 8 363 550 or 64 52 8 385 713 plus a couple other parts like the conversion receiver/drier, pressure switch, suction pipe, pressure hose, etc

[ELVA164]

Great, thanks guys! I've already got a new PF condenser, receiver dryer, high/low pressure switch, expansion valve, o-rings for everything, and adapters for the fittings. The only things I don't have are the PAG oil for the compressor I'll use and a rebuild kit for the seals in that compressor. I think I was remembering that the Bosch compressors don't work well at all with r134a and didn't know if there were any others like that.

[jeffnhiscars]

A compressor is a compressor. What makes them 'compatible' is the oil that's in them..

Not quite. The oil has to be compatible with the refrigerant but that can be changed. It's the seals that are non negotiable and if you put r134a in the wrong compressor it will break down the seals

There's a bulletin that lists the compressor SNs that are and aren't compatible. Having said that, even an r12 compressor that will tolerate r134a is still an r12 compressor that won't give the best performance with r134a.

[ELVA164]

Not quite. The oil has to be compatible with the refrigerant but that can be changed. It's the seals that are non negotiable and if you put r134a in the wrong compressor it will break down the seals

There's a bulletin that lists the compressor SNs that are and aren't compatible. Having said that, even an r12 compressor that will tolerate r134a is still an r12 compressor that won't give the best performance with r134a.

Maybe that's what I was remembering. Is this the bulletin?

https://docs.google.com/file/d/0B6qMSgbyJMbTNWoyb0YzalNHS0U/edit

[Navarone]

I read somewhere that the compression ratio or something for an r12 compressor is lower than an r-134a compressor, so it'll work but not at the best efficency. It may have had something to do with the best RPM to run the pump at. Maybe just changing the pulley size is enough to fix that? Not sure.

[Ryann]

Not quite. The oil has to be compatible with the refrigerant but that can be changed. It's the seals that are non negotiable and if you put r134a in the wrong compressor it will break down the seals

There's a bulletin that lists the compressor SNs that are and aren't compatible. Having said that, even an r12 compressor that will tolerate r134a is still an r12 compressor that won't give the best performance with r134a.

No. The refrigerant will not 'break down the seals'. POE oil has a softening effect on older refrigeration o-rings in other areas of the system, yes. And as I said before 134a is now certified by Copeland as being compatible with older mineral based lubricants, so using 134a in an r-12 compressor containing mineral oil is not an issue. Also as I've said a thousand times before, charging an e30 system with 134a makes zero sense when there are several readily available r-12 drop ins.

[jeffnhiscars]

Maybe that's what I was remembering. Is this the bulletin?
https://docs.google.com/file/d/0B6qM...YzalNHS0U/edit

Sorry for the the iphone pics but these are the applications and PNs that are NOT r134a compatible according to BMW

I read somewhere that the compression ratio or something for an r12 compressor is lower than an r-134a compressor, so it'll work but not at the best efficency. It may have had something to do with the best RPM to run the pump at. Maybe just changing the pulley size is enough to fix that? Not sure.

Its the pressure so r134 will not be as efficient in a compressor designed for r12

No. The refrigerant will not 'break down the seals'. POE oil has a softening effect on older refrigeration o-rings in other areas of the system, yes. And as I said before 134a is now certified by Copeland as being compatible with older mineral based lubricants, so using 134a in an r-12 compressor containing mineral oil is not an issue. Also as I've said a thousand times before, charging an e30 system with 134a makes zero sense when there are several readily available r-12 drop ins.

Break down may not have been the right term but my understanding is that the life expectancy of the wrong seals in an r134 system is limited. As to whether or not r12 substitutes are a better option, thats a matter of opinion. If you have a supply and can service yourself, perhaps, but those substitutes do come and go and who knows if/when you will find a shop to service what you have.

There are also guys running propane in their AC...Mehh !!

[Ryann]

O-ring issues occur in the presence of POE. R-12 compressors did not run POE. Research has shown that 134a sufficiently moves mineral oil through refrigeration systems, so seals, o-rings, and compressor 'compatibility' are a non-issue for the OP given he doesn't change the oil. The primary issue I have personally experienced running 134a in e30s is excessive head pressure, likely from an undersized condenser coil.

[ELVA164]

Not changing the oil really isn't an option, as the old system has to be opened and most of the parts replaced. I'll be cleaning the two things I'm reusing, namely the compressor and evaporator, with isopropyl alcohol and pressurized air. I'll admit these posts are a bit unsettling as I head out to do all this...

[ELVA164]

Sigh...now that I ended up not doing the job due to second-guessing, I'm thinking of replacing the three rubber hoses I see. Assuming I didn't miss any they are: Evaporator to compressor (the big one with the heat shielding that goes under the manifold), compressor to condenser, and condenser to receiver-dryer. Anything I'm missing here? My evaporator to dryer line which runs along the fender is all metal, so I won't be replacing it.

As I start looking for replacements, things have gotten pretty confusing. Some suppliers list multiple hoses, not all of them specify the part being R134a compatible or not (aka barrier hose), and some of the descriptions/pictures don't look anything like the piece described on my car. Ugh.