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My car still has the original R12 system & it was serviced a few years ago by the prior owner. It cooled last year but not too well. I've read where these 1971 cars did not have a cycling compressor. Correct? Will my compressor shut down if the freon level gets too low however to prevent damage to the system? I've worked w/ my 1988 Mark VII A/C system, & it cycled when low & even when cooling. I have the factory service manual, but want to be certain it won't wreck itself.
GM hadn't completely figured out CC systems at that time, so no, a 71 doesn't have a cycling clutch.
Some GM systems did have a low refrigerant pressure/superheat switch but I don't recall early 70s A-bodies having it. Cadillacs had it in the 60s and the other full-size GM cars got it in early 70s. Some carlines kept it even after the R4 compressors appeared.
If your car has one of these clipped onto the compressor bracket it has the low pressure protection switch. This is on a 1976 Ninety Eight with VIR system (contains all valves in one vessel).
Last edited by rocketraider; February 24th, 2023 at 08:34 AM.
During my research I discovered the compressor is designed to spray a small amount of oil at the pulley. I just installed a nice white radiator overflow container in my 1971 Cutlass 350. So, I made a small plastic guard for that pulley. Hardly noticed when you look at the engine. Bracket attached where the muffler mounts. Material is a 1 gallon shrubbery pot from the local nursery.
Last edited by Falkon; March 1st, 2023 at 01:23 PM.
Where did you get that research information about the oil spray?
If you compressor is spraying oil from the front pully area the front seal is bad. Think about this, why would the design engineers want oil around the clutch or the belts.
If in fact you see oil you have a Freon/oil leak. This could be why you are experiencing degraded cooling performance.
Where did you get that research information about the oil spray?
If you compressor is spraying oil from the front pully area the front seal is bad. Think about this, why would the design engineers want oil around the clutch or the belts.
If in fact you see oil you have a Freon/oil leak. This could be why you are experiencing degraded cooling performance.
That's in the Factory Service Manual. It states not to replace the compressor if there is a line on the hood insulation from the compressor. It's designed to seep some oil to keep the seal lubricated. Page 1A-13 of the Original Service Manual. The very first thing, top left, in bold print. Seemed strange to me but it would explain why my A/C still blows cold despite this residue. Also below in Post #3 is where I also saw it described best. Apparently, some of the Olds Toronados had a metal guard from the factory too.
Humm...interesting. I've never witnessed said weeping on these A6 compressors.
Handy simple shield you fabbed.
I thought it was crazy too. The inspector who checked out the car prior to purchase said the A/C was no good. I found it blew some cold. This made my day. I think I first saw it in that thread about A/C mess. It hasn't sprayed a lot. I never noticed it until I installed a new white jug for radiator overflow in line w/ the pulley. I like my old cars to look original. This is pretty much hidden. I used this pot w/ the lip to the rear.
Last edited by Falkon; March 2nd, 2023 at 10:15 AM.
Humm...interesting. I've never witnessed said weeping on these A6 compressors.
Handy simple shield you fabbed.
Buick engine have a shield like that from the factory. As for the designed leak, you have to keep in mind the time period the A6 compressor was designed. Like most things made back then, it was way overkill, extremely rugged, and did the job extremely well. The refrigerant was cheap, in one of my A/C classes the instructor told us that they used the refrigerant to blow clean the condenser coils on houses because it was easier that dragging a air compressor around. Nobody knew what the ozone layer was, nobody worried about the tiny leak. As long as the A/C kept you cool nobody worried about that stuff.
Thank you for the explanation of this system. My plans are not to use the car very much. The A/C would be used even less. It was serviced two years ago by the prior owner, & a hose was replaced. I plan to have it converted to R134 in the future, & it'll probably get a new compressor. At present I'll use it as is until it stops cooling.
Last edited by Falkon; March 2nd, 2023 at 05:34 PM.
Thank you for the explanation of this system. My plans are not to use the car very much. The A/C would be used even less. It was serviced two years ago by the prior owner, & a hose was replaced. I plan to have it converted to R134 in the future, & it'll probably get a new compressor. At present I'll use it as is until it stops cooling.
I converted mine over to 134 about 4 years ago when r12 became outrageously expensive and very hard to find. It cost me less than $300 in parts. The only thing that took a little time was sending the POA valve off to get redone for r134.
Run the AC periodically to keep things functioning properly.Sitting for long periods of time is not good.
And reasoning behind that is... to keep the compressor shaft seal lubricated!
Yup. AC systems back then were designed to lose a pound or so of refrigerant in a year's time. It was considered normal. Then the car-hating guilt-ridden neeners made it their mission to make comfortable, conditioned air something bad. Never mind it was a godsend for people with respiratory problems.
You'll never convince me that a combination of car-haters and Big Chemical didn't conspire to eliminate effective automotive refrigerants. The patents (ergo royalties) on R12 were expiring, one of the major players in chemicals had developed R134a but couldn't get anyone interested in it, so get the enviro-fascists in on it and invent an ozone layer catastrophe. The ozone layer hole has existed for millennia and has expanded and contracted with conditions. But guilt-ridden neeners just can't help themselves.
I don't get people who carry irrational guilt over things they weren't involved with and had no control over. I just don't.
February 23rd, 2023, 11:59 PM
