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Discussion Starter · #1 ·
Well this is my first post, and I likely won't have many since I am not fortunate enough to own a vehicle as nice as a Trailblazer. I am on vacation in Las Vegas, and my dad who is fortunate enough to have an 05 Trailblazer 4.2 has developed a problem. This only has about 33k on it. It has a whine. Now I did read the post that was posted about this and what the person found, which was an idler pulley. I would like to describe the sound and see what you guys think. To me it sounds exactly like an alternator that has a short in the stator, an electrical short. I am familiar with that sound as I used to work for a place that specialized in alternators, starters and batteries. We did testing and repair. However I unplugged the alternator and started the vehicle and the whine was still there. There is no problem with the voltage either on the meter or at the battery (checked with volt meter). I'm hesitant to say its the idler pulley as the whine varies in pitch with the changing of the rpms. If it was the bearing I would think that it would have seized by now, as my dad stated that its been doing this for quite awhile (months). I've never known a bearing to last much more than a couple hours tops when its about to go. I'm hoping its something simple. He has limited tools, though I'm good at improvising. I don't really want to randomly start messing with crap as its been averaging a balmy 111 degrees and I'll be working in the heat. This whine does clearly come from the front of the engine on the drivers side. Any input would be appreciated. We are here for a few more days and really would like to get this thing going so we can get the boat to Lake Mead and do some fishing for Striped Bass. Much thanks, and sorry for the length of post.
 

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2004 gmc
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26,181 Posts
You can always remove the belt and spin things by hand and feel for grindiness. The idler pulley is so cheap that it's almost doing on speculation. The idler pulley changes RPM with the rest of the accessories. Just hope it isn't the AC compressor clutch bearing.
 

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2003 chevy trailblazer_ls
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1,708 Posts
If you turn on the AC and the whine is still there, it is not the AC compressor clutch bearing. The clutch bearing is out of the picture when the clutch is engaged.
 

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2003 chevy trailblazer_ls
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5,268 Posts
ive always had a small whine--- Not the idler pulley.
I think its the power steering..
But I mean im at 147,000 +... that whine has been there for as long as I can remember.
 

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Discussion Starter · #5 ·
the whine is there whether the a/c is on or not. I would emphasize that this whine has been there for at least 3 months, bearing should have seized by now. It does sound a lot like what your power steering pump sounds like when its low, but the p.s. pump is on the other side of where this sound comes from.
 

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2005 gmc envoy_sle
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does the whine get louder if you rev the engine??,,cause my idler pulley went bad and thats what it did.....i had my shop change mine and it cost 35bucks for the pulley and 25 minutes of labor time.
 

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2009 chevy
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Change the idler pulley :yes::yes:, it is good maintenance, and it will go at some point (all gm idler pulleys do).
Check the belt while your in there, you might need a new one as well.
If the noise persists, it might be the tensioner pulley, but I think it will be the idler.
 

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2002 olds bravada
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:iagree: with the posts above. sounds like an idler pulley. It is a very common in our engines.
 
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