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2005 chevy trailblazer_ls
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101 Posts
Discussion Starter · #1 ·
I have a problem with my 2005 Trailblazer LS 4.2 4wd. There is a loud whining at idle and gets louder at acceleration. its getting really annoying. there are no codes present. but i really want to take care of this to prevent it from getting worse. there is nothing leaking anywhere and everything seems normal except it feels like the engine is slow to rev back down when i release the pedal. i am not that familiar with this engine and its been great up till now. any thoughts will be appreciated. it will be going to the dealer next week if i cant figure it out. sounds like a water pump or or power steering pump going. or even a vacuum leak.

thanks

Alan
 

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2004 gmc
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26,181 Posts
If it sounds like an F16 on afterburner, it's most likely a bad fan clutch. Search for many, many previous threads on changing it yourself. Factory design error we're left to pay for.

It could also be a bearing in the idler pulley. Fortunately, this is a cheap part available in the aftermarket for $20-25 and just a few minutes to change. Much higher failure rate than other bearings touched by the fan belt.
 

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2003 chevy trailblazer_lt
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6,568 Posts
get the wife out from under the hood...


anyways now.. sounds like a pulley or the belt is slipping... open the hood with the engine running and see if the idler arm is bouncing around... chances will be most likly be the idler pulley but each is different... and on an 05 sounds kinda odd...
 

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2005 chevy trailblazer_ls
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101 Posts
Discussion Starter · #4 ·
thanks. i have been reading other posts and see its a common problem. i am not that familiar with this type of fan system. i thought they are centrafugal clutch operated but from what it sounds its a electric thing that engages it. i will have a look at it and the idler.

oh and this car only has 25,000miles.
 

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2004 gmc
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It's a very advanced electro-viscous hydraulic unit. Too advanced for its own good, since the first generation design (2002-2005) have a horrible failure rate. ANd it has feedback sensors to tell the PCM if it succeeds in achieving the commanded RPM.

You'd be astonished what sneaky and subtle stuff they put into this vehicle. I swear you need MORE reading and training to understand it than a seven Cisco routers, four wireless bridges, and a data center-sized UPS in a pear tree. .
 

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2005 chevy trailblazer_ls
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101 Posts
Discussion Starter · #6 ·
http://forums.trailvoy.com/showthread.php?t=42818

after watching the videos and reading that i think i will try replacing the idler pully first. its cheaper and if still now i will replace the fan clutch, if still not its going to the mechanic or the dealer.

does anyone know the part number for the fan clutch? i read i should buy the GM one as the copies are not as good. the idler i will get aftermarket

thanks

Alan
 

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2007 chevy trailblazer_ls
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183 Posts
I had the same or similiar problem but unfortunately I was able to diagnose the problem as the AC Clutch bearing!!!! Yeh, just what I said...I by passed the ac with a smaller belt till I can pull it apart when the weather gets better. To see if this is your problem, simply start and run the truck, then turn on your AC. If the sound goes away.......your a winner....Good luck!
 

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I had the same or similiar problem but unfortunately I was able to diagnose the problem as the AC Clutch bearing!!!! Yeh, just what I said...I by passed the ac with a smaller belt till I can pull it apart when the weather gets better. To see if this is your problem, simply start and run the truck, then turn on your AC. If the sound goes away.......your a winner....Good luck!
My ac clutch bearing is going out also. I bought a bearing but I don't have time to deal with the fan removal part...arrgggghhh.

I just bypassed my ac and one pulley above it. I bought a 69.5" belt and it fits. 70" would be better.
 
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