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2003 gmc envoy_slt
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357 Posts
Discussion Starter · #1 ·
I have searched dozens of prior threads for the last 2 hours but couldn't find any with my particular set of circumstances.

Today, with ambient temperatures at 100F and above, I had driven my 2003 Envoy SLT with 4.2L I6 to the mall with no unusual noises. However, when I returned to the Envoy and started home, I began to hear a loud whine come on at about 2000 RPM and get louder as RPM increased and go away when RPM went down below about 1800 RPM. I've been on this board several years now and read dozens of posts about fan clutches and jumped to the conclusion that it was a bad fan clutch somehow exacerbated by the extreme temperatures even though I had only remembered reading about cold temps showing up clutch problems.

Later in the day after another trip where the same continued to happen, I had my wife rev the engine while I had the hood up trying to see if I could detect any anomalies. No luck. Then I began reading all I could using search on fan clutch and was reminded of other possibilities such as idler pulley or tensioner pulley.

I even listened to to a video of a guy with bad tensioner pulley and the resultant noise was close but I'm just uncertain. I realize it's very difficult to diagnose by verbal descriptions rather than actual events but am interested if anyone has any thoughts on the matter.

It will be very interesting to check things out tomorrow with the engine cool and I'll check it before the ambient gets back to 100F like it's supposed to.

C.B.
 

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2009 chevy
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6,431 Posts
Hmmm, at this point it could be any of your thoughts, plus the water pump, the alt, the ac compressor or the belt.

I had a noise related to the rpm and I changed the belt (nothing wrong with the old belt, just that it was the original) and the noise went away.

Unfortunately, it could be many things.
 

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2002 chevy trailblazer_lt
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211 Posts
When the noise is present, remove the belt and start engine. If noise disappears, you have isolated it to something that is belt driven. While belt is off, spin everything by hand, and see if you can find something that is "rougher" than everything else. If its really bad, it will be very evident.
 

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2003 gmc envoy_slt
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357 Posts
Discussion Starter · #4 ·
I took the vehicle out for a spin this AM to verify a few points so I could give an accurate writeup to the service folks at my Dealer. I became more convinced that the noise is more a roar than a whine which, of course, points to the fan clutch. While I was out, everything quieted down since I was headed to the Dealer, but on the way home it started up again!

So I took it to my Dealer but by the time I got there, it was quieted again! They agree, however, based on my description that the probability is the fan clutch. They offered to take a look but preferred that I drive it a few days and see what happens which is what I'm going to do.

And, of course, on the way home, guess what reappeared!!!

C.B.
 
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