AC clutch sliping

Mektek

Well-Known Member
#1
After a WOT run I noticed something strange happened. When accelerating from 3rd to 4th I would hear a hiss from the engine. The hiss would also randomly occur at idle. While watching the engine I could see the "hiss" was the sound of the AC clutch slipping. On a cold engine it was fine, but when hot and idling it would occasionally slip for a second. Stranger still, the clutch wouldn't disengage when turned off from the control panel. AC performance is otherwise OK.

Does this mean I should be planning on removing the compressor to replace the clutch / compressor? .It looks like a hellish job that I'd rather avoid.
Maybe I should spray brake cleaner through the clutch to clean it????
 
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Mektek

Well-Known Member
#3
Hmmm...... removing the shim will reduce the clearance between the clutch plates - mine look OK. It's probably a good idea to remove the plate and clean and deglaze surfaces. Checking the bearings as mentioned in the link is a good idea too.
 

gpking

Well-Known Member
#4
I replaced the bearing, the clutch plate, and removed the shim on mine over the course of a summer just to baby it along to avoid replacing the whole compressor. I think it was my electromagnet that would intermittently short which caused the initial issue, so each "band-aid" fix would only ever buy me a few weeks of reliable cold a/c before it burned itself up again.

All of the little fixes weren't worth it in hindsight. I replaced the whole compressor and never had an issue again.
 
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Mektek

Well-Known Member
#5
I replaced the relay and then it would turn off at the console, so I thought I found the problem. Drove it for a day and problem came back. When I pull the fuse or relay the clutch disengages. When I use the "system off" button it also disengages. The "AC off" button shows ac off on the display but the clutch is still engaged.

wierd......
 
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Mektek

Well-Known Member
#7
Hah! this is a southern truck - defrost button still virgin:yaay:

I had to use a large pair of channel lock pliers to hold the clutch plate and remove the nut. Not much room to work with the fan in the way. With the shim removed the airgap was gone - but a dragging clutch is as bad as a slipping clutch. I made a new shim half the thickness of the OEM one - that got the clearance right. The simple test is to slide a piece of paper between the plates - it should go through with light resistance.
The hissing sound of the clutch slipping while driving seems to be gone, but It's too soon to consider the problem solved.
There still is the odd behavior of the compressor running while the display shows "AC off". I don't think that's normal.....
 
#8
There still is the odd behavior of the compressor running while the display shows "AC off". I don't think that's normal.....
I think my '07 is doing the same thing. I'll have to check on this too and see with the Tech 2 maybe why it's doing this. Is yours an auto or manual HVAC? Mine's manual.
 

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