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Discussion Starter · #1 ·
Hey,

I bought an 05 Envoy last November and it makes a kinda whining sound, almost like an electric motor or turbine. It is RPM sensitive and the performance of the truck doesn't seem affected. It has done it since I bought it and I can't tell if it's getting worse or I just hear more now that the weather has improved and I'm windows down more.

Does anyone have an idea what this is and should I be concerned? :worried: I sincerely appreciate all help.
 

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2004 gmc
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26,181 Posts
Most likely deterioration is in the fan belt idler pulley. Cheap replacements are available at the parts stores. If it sounds like an F16 on afterburner it would be the fan clutch. Less likely are the AC clutch bearing or the water pump. See if you can localize it by listening with the hood open.
 

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Discussion Starter · #4 ·
I checked under the hood and there is definitely a bad pulley though I can't localize it beyond center to driver's side. I'll get some help with it and tackle it next weekend. Thanks for the direction.
 

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I checked under the hood and there is definitely a bad pulley though I can't localize it beyond center to driver's side. I'll get some help with it and tackle it next weekend. Thanks for the direction.
The very centre is the idler pulley, the roadie was talking about. The ac compressor is below this pulley.
It is very hard to tell where the noise is coming from, but here is a quick check. If the noise stops when the ac is turned on, it is probably the ac clutch bearing. If the noise does not go away with the ac turned on, it is probably the idler pulley.
 

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2005 gmc envoy_slt
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If the above doesn't seem to work, you can try this...

Take a piece of hose...one end to your ear and the other end to the parts you suspect are making the noise. Be careful where you put your hands! The noise will be loudest when you've pinpointed it with the end of the hose. If the noise doesn't get louder, it may be at the other end, in your head. just kidding!

It basically works as a primitive stethoscope. Works with hisses, clings, clangs, etc. :thumbsup: haha.
 
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