Automotive Air Conditioning Information Forum (Archives)

roaniecowpony on Sat October 02, 2010 12:17 AM

Year: 2003
Make: GMC
Model: Sierra
Engine Size: 6.0 L
Refrigerant Type: 134
Ambient Temp: 85
Pressure Low: 45
Pressure High: 212
Country of Origin: United States

I was attempting to help a co-worker out. I overheard him on a phone con with a dealer where they wanted over a $1000 to replace his compressor "because the clutch was too weak". I mentioned to him, that often, the clutch wears to the point the gap becomes too large to allow the clutch magnet to pull plate to engage. That had been my limited experience anyway.

BTW, I'm returning after a few yrs of having been away from here. I learned enough to be able to replace compressors, test pressures, evac and recharge, etc. all from here. Still, I'm a novice and do this very infrequently.

Back to my story. I offered to attempt to adjust the clutch and also to put my gauges on his system to check it out. I showed up with my tools today at work and saw the gap was big, around .025-.030 or so. I dug out my MasterCool clutch tool kit, but for the life of me, couldn't figure out which tools fit his compressor clutch. I couldn't see the front of the clutch with the tight spaces and eventually gave up. There was no large internal thread I could feel and it seemed like no small externally threaded shaft.

So, I went onto something I thought I could help with...the gauges. I installed a jumper in the low pressure switch circuit and had him start the truck. I tapped the clutch and it engaged solidly. I told him that was a good sign and that his clutch was probably fine and just needed adjustment. I hooked up my gauges and the pressures were 22/150 at 85F/50% humidity. I said it looked like it was low on freon as well. Vent temp was not good either. He said it had been serviced about 6 months ago. I told him it could have a slow leak. I put in a almost 2 cans of 134 to get the pressures to 45/212. It was working great. I pulled my gauges and the jumper. It seemed to engage the clutch a couple times. He left with the a/c working.

Still, I think his clutch is worn to the point it needs adjustment. Any guidance here would be appreciated. I need to figure out how to adjust this clutch.

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Chuck

Edited: Sat October 02, 2010 at 12:25 AM by roaniecowpony

GM Tech on Sat October 02, 2010 7:59 AM

It is a Nippondenso compressor--no longer a delco or delphi unit on an 03..so it is no longer a press fit....you remove the shaft nut (10mm) and slip the clutch off the splines- be careful to not lose any shims from in behind, then remove the thickest shim in behind the clutch- then put it back on and put the nut back on and be happy..

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

roaniecowpony on Sat October 02, 2010 10:56 AM

Thanks much.

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Chuck