It is the A/c clutch pulley, You can't buy just the pulley . A/c isdiffrent from ones in the past. Dealer wants $800 for new compressor. Found GMparts direct.com $406 gmpartsdirect.com: Alternate GM Catalogthis place $365. I ordered it should be here next week. Problem solved.

 

Changed the idler pulley its the A/c pulley noise stops when A/c is on . Dealer wants $800 for new compressor.Nobody has just the clutch pulley new design 2003ChevroletTrailblazerA/C Compressor from DiscountAcPartsWants $365 ordered it should be here soon.

 

I have an '03 TB LT with about 70k on it and I notice a high pitched whine too, but I only hear it when I'm accelerating (for the most part). It sounds like it's coming from the passenger side. I'm pretty sure its not the power steering and I hear it when the A/C is off, so is the idler pulley most likely the culprit? On another forum I saw the tranny pump mentioned... would that make a similar noise?

 

I would say the tensioner . They would scream when bad

 

Had same problem with 2006 TB. 39000 miles
Dealer said idler pulley then after replaced said a/c compressor
GM covered under warranty eventhough it had expired, you know good faith

 

Well I just changed out the idler pulley and the sound is still there (because it was a cheap easy fix). I read on another forum somewhere, a tech saying to remove the serpentine belt and run the engine to see if the noise stops (not too long though without the belt!). Then you canconfirm thatit is definitely one of the pulleys. I think i'll try that next. Going low dollar to high dollar, parts need to be replaced anyway, high mileage TB 03. [&:]

 

idler pulleys are easy to change on the TB...
loosen the serpentine belt- and put the new one on...
part is $15-$20 new.
a ratchet and a breaker bar will do. Maybe 15 minutes to change?

 

Changed both the idler and tensioner pulley, noise still there. I ran the TB without the belt and the noise disappeared, well i gues it must be the AC like people are saying here[sm=boosign.gif]

 

Hello All, great ideas on here by the way, really helped start the ball rolling, anyway...2005 TB, changed the idler pulley assemble noise still there, ran engine with out belt (briefly) and no noise. However, unlike some of the other comments on here, the whine is there whether the A/C is on or off! Not sure it's the A/C, is it possible that it could be the fan clutch assemble? I think I hear that whine in that area. What do you all think? Thanks for the help.

 

Problem is usually not in the fan clutch......my TB whines when its cold outside and goes away when it warms up....the bearing in the alternator is starting to go on it.
Get a long extension, and hold it to metal parts near pulleys. Put your ear on the end of it, and try to find where the noise is the loudest. or get a mechanic's stethoscope

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