tmc

My '02 GLE has 74K miles had a 1X problem when I turned on the a/c. After starting the car, I turned on the a/c and it didn't go on but made a screeching noise somewhere under the hood. I turned off the a/c and car and restarted it. It worked fine and has ever since. I am concerned that there is a more serious problem as I don't believe mechanical devices fix themselves (go away).

Has anyone has this problem? Any suggestiones in diagnosis?

Thanks,

John

KRRZ350

iTrader: (29)

Ok, so from the passanger side wheel well behind the splash sheilds is the a/c compressor. It has a big pulley on it, to the right of the crank pulley. The belt spins the a/c compressor to force gas through the lines into and out of the cabin where they expand and contract so they can remove the heat and moisture from the cabin. However, the pulley on the front of the a/c compressor is usually in a free-wheeling state, meaning the very outer part of the pulley just spins but the whole pump itself doesn't spin and pump the gasses until the a/c compressor clutch is activated (energized), and even then it will cycle itself on and off to mantain a specific pressure inside the lines.

So, say you had the serpentine belt off and were looking at this a/c compressor, if you were to spin the outer part of the pump it would spin very easily with practically no resistance. But if you were to take your fingers and attempt to spin the inner part of this pulley/clutch assembly, since that is the inner part of the clutch and is locked to the shaft of the pump it would be very hard to turn the inner part and you would actually hear and feel it going "pump pump pump"

What happened in your case, was that this one time when you called on the a/c, the system energized the clutch to engage the outer part of the pulley with the inner part, except for some reason or another your actual pump was very resistant to this or even frozen up or jammed, or simply the serpentine belt didn't want to have anything to do with it because it couldn't get traction, whatever the reason when the clutch locked up and tried to spin the actual pump instead of the belt now spinning the pump it couldn't so instead the belt slipped on the pulley that it could not turn and made a really loud screeching sound.

I don't have a bit of advice at all as to what went wrong that one time to not make the belt able to spin the actual compressor, but hopefully by understanding exactly what went wrong and a few basics about the system it will help you if the problem creeps up again. I wouldn't worry about it, I would however make a quick inspection of the serpentine belt, which if it is original is probably very cracked and shiny. Replacing the serpentinebelt will give you a good oppurtunity to play with spinning the compressor clutch etc and understand what I'm talking about.

tmc

Thank you for your detailed analysis and explanation. I will inspect my serpentine belt and assuming it is cracked or looks like it needs to be replaced, will replace it and play with spinning the compressor. I am glad that you believe it is a one-time occurrence but will definitely look into this and hopefully prevent it from happening in the future as I live in Florida and need my a/c.

Again, thanks for your assistance.

John

ghostrider17

iTrader: (6)

6 yrs & 65k miles, I've noticed that my S-belt is getting worn - so I'm having it replaced tomorrow at the Stealer.
I've noticed that my A/C compressor is making some odd noises as well while engaged...I'll be curious to see if the new belt helps this.
I'll repost my findings.

gr

Maxgig

iTrader: (5)

a new belt should fix the problem

hybridioN

iTrader: (11)

a similar problem just happened to me. my ac compressor seized up, and somehow cracked my alternator. does your AC still blow cold air?