2005 Chevy Trailblazer - engine whines

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  #1  
Old 07-26-09, 10:30 PM
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2005 Chevy Trailblazer - engine whines

2005 Chevy TB 6cyl engine, aprox 50k miles. Engine seems to whine alot during acceleration. Thought it was the tranny but I hear it while revving in neutral. I saw another TB pulling out of a parking lot and it actually sounded similar, can this just be something inherent with these trucks?

Thanks.
 
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Old 07-27-09, 10:27 PM
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Sounds like (without hearing it ) you may have a bad idler or tensioner bearing also with 50k check your belt for cracking on the inside and "scoaring" on the outside.
 
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Old 07-28-09, 08:39 AM
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I just read on a complaint site (carcomplaints.com) for my year/model that the whining noise (2 complaints) was a pulley bearing gone bad. Is this the same as the tensioner bearing you are talking about?

Is this something I can fix or am I better off taking it into the shop? Truck has never been to the dealer since we bought it in 2005, only into local shops for routine maintenance.

Thanks.
 
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Old 07-28-09, 11:49 AM
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The electronic fan clutches go bad and moke a loud noise also. It is a roaring noise though. Also Alternator bearings could be going out.

Pulley bearing and idler are the same thing. Tensioner is different.
 
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Old 07-28-09, 12:43 PM
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Get a mechanics stethescope and check 'em all, you should be able to find it pretty quick.
 
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Old 08-01-09, 04:27 AM
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Ok, I picked up a mechanics stethescope yesterday, now what?? I can find the alternator, and probably the fan clutch and have a listen. I would assume when I rev the engine the noise should get extremely loud through the scope?? Noise is really noticable as engine revs.

How do I check the pulley bearing and tensioner? are these just sealed bearings along the drive belt?

Thanks.
 
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Old 08-01-09, 01:48 PM
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Start the engine. Place the end of the scope on the bolt that secures the pulley to the front of the engine. It's either gonna be the idler or tensioner pulley, as them are very, very well known to fail. We replace a dozen every week.
 
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Old 08-01-09, 01:53 PM
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And if you can't get to the bolt safely (sometimes hard to do with the shrouds and covers nowadays)...just going to the back of the mount for the pulleys normally works as well....
 
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Old 08-02-09, 09:06 AM
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I only had a few minutes to work this morning, but I listened with the scope and here's what I noticed - alternator made a loud noise, but not the whining noise, thought this may be normal. Placed the scope on a couple of bolts holding the pulleys, and also the alternator bracket & bolt. THis is where I heard a somewhat whining noise. I was working alone & couldn't find the throttle cable to rev the engine, so I will check again later when I have more time. Is this the sort of thing I am listening for? When I find the culprit, should it sound exactly like the whining noise that I am hearing, but much louder through the scope?

Is the tensioner the little bracket that appears to be loose that is toward the lower part of the engine? This seemed to be ok, made a little noise but I think it was just a vibration from the movement. Not sure, but I would think that's how the tensioner should operate, that it should keep the proper tension in the belt??

Oh, the belt, from what was exposed, looked ok, no cracks or scores.

The last car that I did major mechanical work on was my 79 pontiac, so please bear with me.

Thanks.
 
  #10  
Old 08-02-09, 09:33 AM
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It won't sound exactly the same since it is being transmitted through metal instead of air.

IIRC when mine was bad..it was much higher pitched through the scope, since it was traveling through a denser material..that may make sense. You can also sort of isolate it some by using a piece of garden hose or similar. Block one ear..hold the hose to your other. I've stuck a funnel in the end to get to the general area..then just the hose..then the scope. Thats more for lifter or injector noises though, which side..front or rear..etc
 
  #11  
Old 08-12-09, 05:51 AM
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I isolated the idler pulley as the culprit. Found another forum just for Trailblazers and Envoys and there was a post with a bunch of pictures of the pulleys, and how to remove the belt - which I don't think I would've figured out on my own. Thanks to all your help I found the bad part and replaced it myself. Part cost $17 plus the stethoscope $10. Probably saved hundreds by not going to the dealer or shop.

Thanks Again, truck sounds great!!
 
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Old 08-12-09, 08:15 AM
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Glad its fixed and running ok.
 
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Old 08-12-09, 12:41 PM
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You could have cut the belt to get it off, but getting the same belt back on would be impossible.
 
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Old 08-12-09, 01:01 PM
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NOP ever try to cut through a serpentine belt? Like trying to cut through the bead of a tire sometimes.
 
  #15  
Old 07-24-10, 10:27 AM
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Just located this problem on my '05 Trailblazer with only 35,400 miles. I used about a 6' piece of garden hose as a stethoscope and pin pointed it as the idler pulley. Replaced the idler pulley and all is well now! Quiet and smooth! I didn't see anything wrong with the old bearing while I had it in my hands but I understand bearing problems can be very elusive. $20 at Autozone, one bolt and serpentine belt to remove, and 15 mins is all it takes. Very easy fix. Below is the front and back of old bearing. It didn't even make a sound in my hands as I spun it. No slop either. But it was causing the problem.



 
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