A/C has Failed

[copperhead]

After 77k my A/C has failed. First it was hot air and then a manual cycling of the compressor (toggled on and off through panel) revealed deep grone. Visual inspection reveal molten rubber which appears to have been part of the isolator/coupler between the clutch and pully slung all over the place. The question is, did just the clutch fail do to the rumored overcharge of some of the 2003 model year or do I need a compressor as well? I can rotate the compressor through the bolt that attaches the clutch. My plan right now is to just replace the clutch and if it runs, check pressures with a guage set. Any knowledge transfer would be appreciated. It is a 2003, Duramax.

[More Power]

You can rotate the triangle shaped metal piece at the front of the A/C clutch as well to check to see if the compressor part of it at least rotates and feels somewhat normal. By hand, it should feel stiff when slowly rotated, but without any grating.

The clutch can be replaced separately, but I'd try energizing the clutch using test leads (engine & key off) with the electrical connector disconnected - just to satisfy my curiousity.

MP

[markrinker]

My A/C went from blowing cold to nothing today. Clutch is still engaging, no bad noises or anything.

Its a 2003. Whats the story on the overcharging?

[copperhead]

I don't know what the full story about overcharing is but I had performed some searches on the forum and had seen some posts regarding overcharge conditions. Now, I will say I had experienced the hot air two days earlier with no other symptoms, then it just went away. Then two says later, it was all over, clutch gone. So I'm ordering a clutch and going to put the guages on it if it will operate, I believe my compressor is still ok.

[copperhead]

I have now heard that one problem has been the overcharging of oil in the system and I am now wondering how many compressor failures have been experienced in trucks with say over 75,000 miles.

[Jim Brzozowski]

I suggest that molten rubber you saw was the result of the clutch slipping and not driving the compressor enough, thus the hot air a couple of days before. Probably only the clutch is shot. Should not have hurt the compressor.

[madmatt]

intermitent A/C inop is probably a low pressure switch, the freon overcharge is usually a constant cool but not cold or only gets cold while going down the road and only slightly cool while idling, the oil overcharge problem has been w/ new compressor installions. The new compressors are being shipped w/ 8 oz of oil in them whereas the old ones were shipped w/ out any. Techs were simply adding the standard 2oz w/ out reading the provided paperwork,(unknowing there was already 8 in there) installing the compressor and the a/c was still inop. Copper head, when you remove your compressor make sure your a/c belt tensior is not broken. if so your expiencing "liquid slugging" Your dealer has the bulletin on this and will know what it takes to correct it.

[Quack_Addict]

I use the A/C in my HD infrequently. The last couple times I used it (several weeks ago), I turned it on while driving on the highway and it let out a loud SCREECH as the clutch/compressor spun up.

Yesterday I went to turn the A/C on while picking food up at a drivethrough (engine at idle) and it started screeching - and wouldn't stop until I drove about 100 yards down the road - even though I turned the A/C off immediately (and the system wasn't on 'recirc').

My truck has the 6.0L with 85k on it.

[copperhead]

Well, my new clutch should arrive on Monday. I should learn alot at that point.

I was also told by a reliable source that these compressors have an avearge failure rate of 85k miles. I have trouble believing this as I don't hear of that many people with GM products going in to get their AC rebuilt.

[madmatt]

I do change quite a few of these compressors on trucks, tahoes, Subarbans, etc,etc,ect...but usually it is not for A/C inop concerns. The most often seen failure @ my shop is just noise from liquid ingestion/slugging.

[copperhead]

Well, the clutch has been replaced and the compressor seems to be just fine. The clutch plate seperated from the hub that drives the compressor shaft. They are held together by a hard rubber isolator which broke loose at the hub contact point, liquified and sprayed all over the place. The question is why did it fail? I would say that it was either breakdown due to normal Texas use (combination of heat and stress over time) or I had a high pressure high heat situation that softened the rubber at the time of failure. Maybe my clutch was slipping at the time and contributing to the heat. I put guages on it and it appears off a bit but not terrible. We are going to take it in and have it checked out. Along with a surging idle that is inconsistent and the tailgate cable recall.

[copperhead]

Madmatt, you mentioned making sure the A/C belt tensioner is not broken, I'm assuming you mean THE belt tensioner? It still requires a hefty amound of leverage with a 1/2 inch drive to release the tension, so that seems to me to indicate that it is fine???

[madmatt]

Yeah, I'm sorry. Gas engines have two belts and tensioners. My bad The liquid slugging has not been a issuse w/ duramax's either......I really need to pay more attention to what I'm saying, it's easy to get confused going back and forth from gas to diesel all day.

[copperhead]

Well, after the clutch was replaced, a test drive showed that it cooled fine while in motion but not well while sitting still. The dealer says its the compressor, I have a problem with that but it could just be my ignorance of these compressors. I guess its possible that it is somehow damaged in a way that prevents it from working efficiently while at low RPMs.

[jbplock]

Copperhead,
Not sure is this is related to your problem but when my 03 was new the AC didn

[copperhead]

Well, I don't think it is as it was working find up until the weekend when the clutch went out, so that is what leads me to believe that there is a bigger problem. What intrigues me is that there could be a compressor problem even though it runs find now with the new clutch but just doesn't cool well while sitting still. I wouldn't know how to find out if I had the latest A/C programming?

[copperhead]

Turns out it is the compressor. I have had a noise for at least 18month. A high pitched chirp, sometimes a long duration chirp (1/2 second or less). Turns out, after spending some time with my wife at the throttle in the driveway and my head under the hood, that it was been the compressor all along. When I first heard it over a year ago I was convinved it was a fan clutch or belth issue but never really spent the time on it. This time if you raised the RPM up to around 1200-1500 and held it it would chirp frequently. After getting my thinking cap on and having her turn off the AC, the chirp went away. I suspect the cluch failed earlier because it actually locked up momentarily. Parts are on the way.