A6 Compressor oil viscosity?

[Tom L.]

Anyone know what is the preferred viscosity for A6 compressors? I'm planning on using Ester oil over PAG since that's what I have, just not sure if I should use 100 or 150 viscosity. All comments welcome, thanks!!

[Edward J.]

Re: A6 Compressor oil viscosity?

Tom are you converting the system to R134? that Is what pag or ester oil is for. R-12 uses mineral oil. I would not convert a older R-12 system to R-134 I don't think you'll be happy with R-134 as it does not have the cooling of R-12 and creates higher pressures when hot, Corvettes have enough problems with air flow as it is, On a hot day you'll find the cooling is not great. these higher pressure re-late to more compressors issues and higher engine Temps when in traffic as the condenser temps rise. Big Blocks seem to have enough issues keeping cool.

[Jim T.]

Re: A6 Compressor oil viscosity?

R12 use installed at the factory used 525 oil which is available at NAPA and other automotive parts stores and is not the same type of oil used with 134 systems.

[Dick W.]

Re: A6 Compressor oil viscosity?

Ester is compatible with either above mentioned refrigerantsrefrigerants

[Tom L.]

Re: A6 Compressor oil viscosity?

Dick is correct, Ester is reverse compatable, perhaps the reason it is the lubricant of choice in commercial use. I've converted hundreds of commercial systems from 12 to 134a over the past 20 years, it is a fine refrigerant. I think there is a lot of mis-information out there regarding 134a, not only in the automotive world but the commercial end as well.

System set-up is a key part of making it work. Things like hoses, seals, oil and the POA valve need attention. ALL mineral oil must be removed as well since it is not miscible with 134a and will drag the oil out of the compressor and prevent return. Since I'm starting basically from scratch with this system I feel confident that it will be fine. Worst case scenario is I go back to 12 since the hoses, oil and seals will be suitable for 12.

[Dick W.]

Re: A6 Compressor oil viscosity?

Dick is correct, Ester is reverse compatable, perhaps the reason it is the lubricant of choice in commercial use. I've converted hundreds of commercial systems from 12 to 134a over the past 20 years, it is a fine refrigerant. I think there is a lot of mis-information out there regarding 134a, not only in the automotive world but the commercial end as well.

System set-up is a key part of making it work. Things like hoses, seals, oil and the POA valve need attention. ALL mineral oil must be removed as well since it is not miscible with 134a and will drag the oil out of the compressor and prevent return. Since I'm starting basically from scratch with this system I feel confident that it will be fine. Worst case scenario is I go back to 12 since the hoses, oil and seals will be suitable for 12.

Complete evacuation of the system is paramount, to many think that a 20 minute pump down of an open system is adequate. Given the time, I always evacuate the system over night after making sure there are no leaks. Maybe I practice overkill, but from experience more is better, ever smelled 20 tons of spoiled poultry?

[Tom L.]

Re: A6 Compressor oil viscosity?

Dick is spot on target. Often it's the little things that make the biggest differences. On e that has not been mentioned is the air inlet of the evaporator, if clogged cooling will be non-existant. I luckily found that mine was badly clogged a couple of years ago when I had a "while I'm there" moment. The heads were off the motor and there was a badly patched small hole in the evaporator housing. Couldn't believe what I found, mice had been at work sometime in the car's life. Check the pic.

And back to the original question, is 150 viscosity correct?

And yes Dick, I've smelled all that rotten chicken, just awful. FYI, veal is a lot worse!

Clog.jpg

[Edward J.]

Re: A6 Compressor oil viscosity?

I have converted hundreds of R-134 systems in my automotive business also and know of the ups and downs, the problem I have is the replacement of receiver dryer, O-rings, low pressure switch , flushing of system,Hoses and have done this with only satisfactory results with air temp. form ducts when idling in hot weather. with r-12 still out there, its still cheaper to re-install the R-12. than to replace the parts, another key is the system pressure is different as you say Tom POA valve operates on different pressures. Tom keep in mind there is a formula for re-charging the system with 134 and it does not require as much. And yes ester is compatible but is not a oil of choice for R-12 Freon.Tom, these are only my opinions and knew that there is other opinions with R134. I am not down playing this as there are some system that will work fine w/134 but generally its the later 70s/80s and earlier 90 autos. your car is starting from ground zero?? another issue down the road is 134 will it become like the r-12, who knows.

[Larry M.]

Re: A6 Compressor oil viscosity?

Autoacforum folks recommend Ester 100 viscosity for your application. See link http://www.ackits.com/c/Compressoroi...ssor+Oils.html


I have not used ester lubricant personally, but agree that it should be fine for your application. I have always stayed with R12 and mineral oil in these older systems. The Autoacforum is an excellent source for knowledge, experience, and specifications, etc for these systems. They also sell excellent replacement parts and ac service equipment.

FWIW

Larry

[Dick W.]

Re: A6 Compressor oil viscosity?

? another issue down the road is 134 will it become like the r-12, who knows.

R1234yf is already out there. Probably will be the only OEM refrigerant used by 2017, if not before. OEM's are pushing for an earlier date than EPA has set. European cars are already using it as is, I believe, some GM cars built here.

[Edward J.]

Re: A6 Compressor oil viscosity?

Dick, There was some talk about the newer refrigerant being released soon. And I guess we will see what becomes of 134 only time will tell. At one time I remember all the junk cars that left my shop having a R-12 system we would recover the system saving the liquid gold. and even the junk yards brought a A/C machine to just recover the Freon. Kind of like the used cat. convertors now, they can be worth a small fortune.

[Dick W.]

Re: A6 Compressor oil viscosity?

Dick, There was some talk about the newer refrigerant being released soon. And I guess we will see what becomes of 134 only time will tell. At one time I remember all the junk cars that left my shop having a R-12 system we would recover the system saving the liquid gold. and even the junk yards brought a A/C machine to just recover the Freon. Kind of like the used cat. convertors now, they can be worth a small fortune.

Beginning 1/1/13 all European built cars were equipped with the new refrigerant, 2017 is the drop dead date for domestic vehicles, Glad I am out of the repair business, everything I own is now 134 equipped, have almost 30# of 134 for use in them and probably 40-50# of R-12 to dispose of.

[Edward J.]

Re: A6 Compressor oil viscosity?

Just 2 more years and I am hanging it up. Only to enjoy the Corvette hobby and help out friends with there cars. and look for a warmer climate in winter.

[Tom L.]

Re: A6 Compressor oil viscosity?

So 100 viscosity is OK for these compressors, that's good since I have a bunch.

I understand the problems with the idea of a clean system. I just finished re-sealing my compressor with the correct seals, I have no refrigerant lines so they'll be good for 134a, all o-rings will be compatable, I'll use this (http://www.nucalgon.com/products/tsp/rx11-flush) to flush the condenser, TXV (It's operation ios a wild card) and evaporator since they are the only parts that came with the car and I'll deal with the POA, I have a P/T chart. Just tried to bench test the POA but it's stuck open, I'll be dealing with it. And since 134a is pretty cheap (About 150 for a jug) I'll have it for a while.

Europe has recognized that 134a is a really bad greenhouse gas. It will everntually go by the wayside but like all refrigerants it will get replaced by something. Been there, done that.

[Dick W.]

Re: A6 Compressor oil viscosity?

Just 2 more years and I am hanging it up. Only to enjoy the Corvette hobby and help out friends with there cars. and look for a warmer climate in winter.

Since November I have only opened my toolbox twice, hunting screwdrivers and pliers. Have started selling my speciality tools, I am planning on only doing basic maintenance to my vehicles in the future. Only work in the past couple of years has been oil changes and tire rotations.