AC issue on the wifes suburban

[Destroyer]

I may just be stating something that you already know, but slugging a compressor is when you introduce a "slug" of liquid refrigerant into the compressor itself. Since liquid is not compressible, it causes the compressor to lock up. If the compressor is locked, then the belt will usually either fly off or break. Sounds like that is what the book is talking about. Eventually the liquid will usually turn back into gas, and the compressor will return to proper operation, making it look like the problem was someplace else. An overfilled system is usually the cause of slugging, but I have seen cases where the air passages in the evap coil are so clogged with hair or leaves that the the hot liquid cannot completely boil off in the evap coil and so it returns as liquid back to the compressor.

[THEFERMANATOR]

Originally Posted by Destroyer

I may just be stating something that you already know, but slugging a compressor is when you introduce a "slug" of liquid refrigerant into the compressor itself. Since liquid is not compressible, it causes the compressor to lock up. If the compressor is locked, then the belt will usually either fly off or break. Sounds like that is what the book is talking about. Eventually the liquid will usually turn back into gas, and the compressor will return to proper operation, making it look like the problem was someplace else. An overfilled system is usually the cause of slugging, but I have seen cases where the air passages in the evap coil are so clogged with hair or leaves that the the hot liquid cannot completely boil off in the evap coil and so it returns as liquid back to the compressor.

The problem seems to follow dual A/C units and GM's idea of not routing the low side line from the rear evap into the accumulator before the compressor. For some reason GM ran the rear air return straight to the compressor which is where the problem stems from. ALOT of compressors from 92-95 were lost because of liquid getting returned to the compressor and slugging it before GM came out with a revised expansion valve for the rear A/C unit. The big problem comes into play with people not turning on the rear A/C units fan, this is what allows the most liquid to hit the compressor.

[Destroyer]

Originally Posted by THEFERMANATOR

The problem seems to follow dual A/C units and GM's idea of not routing the low side line from the rear evap into the accumulator before the compressor. For some reason GM ran the rear air return straight to the compressor which is where the problem stems from. ALOT of compressors from 92-95 were lost because of liquid getting returned to the compressor and slugging it before GM came out with a revised expansion valve for the rear A/C unit. The big problem comes into play with people not turning on the rear A/C units fan, this is what allows the most liquid to hit the compressor.

Yep, that will do it. Hard to believe they didn't run the rear back into an accumulator.... but then again, this is an automotive maker, and they (all of them) are known for pinching a nickle until the buffalo sh!ts.

[THEFERMANATOR]

I was just talking with a friend of mine who runs a shop and he has been having alot of these of late. He said that replacing the compressor wasn't fixxing them, but using a belt off of an 09 is working. He said in 09 GM did away with the tensioner, and went to a stretch belt. You take the compressor loose, slide the belt on, and then tighten it back down. He said that this has fixxed every one so far without a compressor or tensioner change.

[spareparts]

gee thanks, I just got the wife's car back last week. I had them put a new compressor on it. he said the compressor was bad, the guy called me later int eh day and told me the pressures were high, that the clutch fan was bad and not cooling the condenser enough. he charged me $75 for the clutch and $25 to put it on, after that, the pressures fell in line. Total to get the wife happy for the time being $625. He quoted me $525 to fix the ac on the 99

[THEFERMANATOR]

Originally Posted by spareparts

gee thanks, I just got the wife's car back last week. I had them put a new compressor on it. he said the compressor was bad, the guy called me later int eh day and told me the pressures were high, that the clutch fan was bad and not cooling the condenser enough. he charged me $75 for the clutch and $25 to put it on, after that, the pressures fell in line. Total to get the wife happy for the time being $625. He quoted me $525 to fix the ac on the 99

GEEZ, I do compressors on them for about $350-400 including parts, gas, misc, and labor if I buy the parts locally. If I order the parts you can get the kit with a NEW compressor for well under $200 shipped, and I always have a 5% discount available anymore to help cover shipping. I guess I need to start charging more.