ophidia

'08 STX 4.6L 4x4. It always had a bit of a chirp when first starting up in the morning, but now that it's gotten cold out it's gotten quite a bit worse, and doesn't stop until the truck is fully warmed up (longer than it takes to get to work). It's driving me NUTS.

I've replaced both smooth idlers, the pulley on the tensioner, the clutch bearing on the A/C compressor, and the belt (with an O'Reilly store brand). STILL_FSCKING_CHIRPS. No change.

I used a mechanic's stethoscope to check all the pulleys and accessories I could-- no chirp through that from any of the idler pulleys, the ps pump, water pump, alternator, tensioner, or a/c compressor (before I bumped it against the fan and the fan ate it). I pulled off the clutch center on the compressor and started it up to see if the chirping went away, no difference. The only noteworthy thing is when the a/c clutch locks in the chirp lessens dramatically, and I noticed that the tensioner moves when that happens.

What should I do next? This is killing me. Could the tensioner be weak and letting the belt chirp, and when the A/C compressor kicks in, the additional strain tightens the belt and stops the chirp?

Things like this drive me nuts. Absolutely nuts.

05jakev

Wait till the truck has set and is cooled off and take the belt off. Then start the truck and see if it goes away. Then you will know if its an acc. or something in the motor. Of course dont run it very long cus the water pump is not running. If it stops then your back at square one and have to find out which acc is making the noise but you can rule out the motor.

I would guess its the fan clutch. It kinda free spins until the motor heats up.

FX4RubyRed

Try putting wax on your belt. I did it inmy Chevy and it helped .

techrep

iTrader: (1)

try buying a quality belt...like a Gator back... hold a wire brush to the underside of the belt at idle...if the chirp goes away..go get a gator back...you should not put anything on your belt...it will transfer to all your pulleys

ophidia

I'll try the wire brush on the bottom of the belt thing a little later today. I hope it's not the fan clutch because it's an electric one and they appear to be expensive. I spun the fan with my hand and didn't feel or hear any roughness to it, but it's hard to tell with that.

ophidia

I'd tried to find a gatorback locally when I replaced the belt on Sunday, but of course nobody carries them locally. If it shuts up with the wire brush trick I'll have to hit up Amazon Prime.

techrep

iTrader: (1)

Rockauto.com

ophidia

Forgot to mention that I scrubbed the smooth pulleys with brake cleaner and steel wool, and the ribbed ones with brake cleaner and a wire brush, about 2 days ago. It didn't chirp for about 30 seconds after doing that then started again. It did sound strange until it started chirping again though.

05jakev

If you got Electric fans its not the fan clutch

ophidia

I don't have electric fans, it does have a clutch, it's just electronically controlled. I think it's a viscous clutch with some sort of electronic lockup.