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2004 chevy trailblazer_lt
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18 Posts
Discussion Starter #1
I have a 2004 Blazer with Vortec 4.3 I6. ~73K miles.

When I push down on the gas pedal in drive, a whistling noise ramps up like a tea kettle. About half way to the next gear, it dies off and starts again shortly in the next gear. It is very loud when the engine is cold, but quiets down slightly after the engine reaches normal operating temperatures.

Doesn't seem to be intake or injection because the engine accelerates just fine, idles and runs. Plenty of power and no noticeable decline in gas mileage.

I'm worried this is an EGR valve or something that isn't monitored because there is also no Check Engine light.

Thanks!
 

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2003 chevy trailblazer_lt
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39 Posts
I have the exact same noise in my '03 TB, w/ I-6 with 103K. It whistles when I start driving in the morning and gets louder when I accelerate and decreases when I decelerate. After 2 miles it goes away. Could it by related to the fan clutch? I'll be interested in hearing from others with this symptom and of course any ideas or suggestions. Thanks. P.S. Sorry I don't have the answer.
 

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2007 chevy trailblazer_ls
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156 Posts
Mine does almost the same thing. When I hit the gas it will make the noise about halfway through the gear and then let off. Never does it ideling, rarely on decel, almost alway accel, sometimes crusing. I am going to try and take the thing in cause it is annoying. I'll update if they find something.

-Bryan
 

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2005 chevy trailblazer_ls
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20 Posts
Got the same noise took it to a mechanic and they said they have no clue what it is but it doesnt seem like anything is wrong
 

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2002 chevy trailblazer_ls
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1,433 Posts
Usually, whistling in sync with engine RPM is a sign of a vacuum leak from a cracked or loose hose. I'd check all the vacuum hoses. Particularly rubber elbows as those tend to go bad sooner than the rest of the lines, and odds would be that it would be a smaller hose since one of those leaking wouldn't impact the performance much but would whistle pretty good. A larger leak will make the engine run funny.

Or, maybe someone installed a turbocharger while you were sleeping :D
 

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2005 chevy trailblazer_ls_ext
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112 Posts
its a turbo! lol jk

mine has a whine noise when i gun the accelerator. reminds me of transformers
 

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2002 chevy trailblazer_lt
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2 Posts
I've heard of a few cases of the transmission/differential fluid needing to be topped off or get clean flush to clear up a high pitched noise resembling a supercharger almost.. something worth checking anyway!
 

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2003 chevy trailblazer_lt
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21 Posts
High RPM whistle

Mine has a whistle at high RPM as well. Will check vacuum hoses and re-post if I find anything.
 

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2008 chevy trailblazer_ls
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6 Posts
I had a whistling sound until I had my rezzy removed. It almost sounded like it was coming from the engine bay and it happened every time I hard accelerated. Not sure if it's the same thing but it was worth the mention.
 
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