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High pitch whistle on acceleration

67674 Views 66 Replies 29 Participants Last post by  RKM
I have a '07 G6 GT that I inherited from my 87 y/o grandfather when he past away in January. Yes, it's red because what other color would an 87 year old man drive. Within the last 2 months I've started noticing a high pitch whistle/noise when I accelerate. If I back off the throttle its goes away. I thought it was brakes at first but I get no noise when I brake at any speed. Only when I accelerate. Anyone have any thoughts? Haven't brought it in yet, want to see if its a minor fix I can do myself.


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Whistle no more....

'07 G6 convert with 45K on it.

Whistled like a bottle rocket on acceleration from about 2k to 3k rpm, never at cruise.

Followed slls and ballerinda's examples and replaced the resonator with a MagnaFlow 10424 from Summit Racing ($68, free ship), 2" in and out, 24" overall, matched the factory resonator and it is stainless to boot.

It is now more better, no hint of a whistle, just V6 rumbly goodness.

As a side note, there was no 'weep' hole or any other factory leak in the exhaust system.


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could be....

Just to be sure check the wear indicator on the tensioner to make sure the belt isn't at its limit.

When I first started tracking down the noise on mine the belt appeared to be past the half way mark on the tensioner so I replaced it.

Didn't fix jack but I felt better.

The Magnaflow kit replaces the muffler, resonator and pipe all the way to the exhaust flange at the back of the engine so if the new resonator is on there the exhaust probably isn't the source.


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@ tensioner question


Forgot to answer this, tensioner on the 3.5 has marks as do most others, indicating the stretch or wear limit on the serp belt. Kind of a moot point though as most belts have so much kevlar etc that they just fracture and break before they stretch any real amount.

Hard to see in the pic below but on the tensioner arm there are reference marks, B & C, that are the wear limit against the mark @ A.

This pic is after I installed a new belt trying to kill the squeal.



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