High pitch whistle on acceleration

I bought my 2007 G6 a week ago and when I test drove it, I heard the whistling noise in the exhaust when I would accelerate beyond 2000 RPM. I started not to purchase it because of that and the fact that the salesman said, "sounds normal to me". So, I came home, searched it out and found this thread. I decided to go ahead and buy. I ordered the Magnaflow 10425 from Summit Racing for $68 and paid a local muffler shop $65 to install (GM dealer didn't want to use my parts). It is fixed and sounds great now! Thanks! By the way, the car was priced $3,300 below value- that could have been how I got it so cheap!

Magnaflow 10424 fixed whistle

Many thanks to slls, ballerinda and x44+ for their posts on replacing the resonator - just had the Magnaflow 10424 (purchased from [ame]http://www.amazon.com/Magnaflow-10424-Stainless-Steel-Muffler/dp/B000XQQ08C[/ame] ) installed by my local Midas shop (about an hour labor). Prior to hearing the OE resonator the Midas tech wasn't sure that would be the cause but when his boss reved the car he clearly heard the whistle at the resonator. After cutting off OE and welding new resonator the result = no more whistle. The car sounds fantastic, good strong but not obnoxious note at rev and restored my for our 2007 G6 HTC.

So for ~$68 for the resonator and an hours labor thank God the whistle is gone.

Thanks for this post. I was wondering wth that noise was when I accelerated. It's been there since I bought the car about a year ago. I will get this fixed asap.

Sorry everyone, on my post, I typed the part # in error, it was the Magnaflow 10424 that fixed my whistling noise also!

My wife's 2007 convertible developed the whistle and I found this thread. I ordered the Magnaflow from Amazon and set up an appointment with a local Midas shop. They had the car on the lift about 30 seconds, came and got me and said look at all this...pointing at what I'm assuming is bracing to stiffen the convertible...and said this is at least a 4 hour job to take all this down and then do the resonator. I told them to drop the car and I'd get it done later, because I did not have that kind of time and I didn't trust they knew what they were doing. Am I correct in assuming that the bracing is not a big deal and they should be able to replace the resonator as easily as a non-convertible? Thanks for your help.

Turns out my 07 GT vert is having this same issue. At first I thought it was the trans, but my buddy looked at it and realized the trans is fine. He removed the cat back part of the exhaust and the sound went away so we realized it's somewhere in the exhaust.

After reading this, it looks like I'm gonna have to spend the $60 and get the magnaflow muffler

sav07g6 said:

My wife's 2007 convertible developed the whistle and I found this thread. I ordered the Magnaflow from Amazon and set up an appointment with a local Midas shop. They had the car on the lift about 30 seconds, came and got me and said look at all this...pointing at what I'm assuming is bracing to stiffen the convertible...and said this is at least a 4 hour job to take all this down and then do the resonator. I told them to drop the car and I'd get it done later, because I did not have that kind of time and I didn't trust they knew what they were doing. Am I correct in assuming that the bracing is not a big deal and they should be able to replace the resonator as easily as a non-convertible? Thanks for your help.

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Hell just take off the bracing on the bottom yourself if they think its that big of a deal, i thinks its only a couple bolts. Then bring it to them and they should have it on for you easy cheesy.

sav07g6 said:

My wife's 2007 convertible developed the whistle and I found this thread. I ordered the Magnaflow from Amazon and set up an appointment with a local Midas shop. They had the car on the lift about 30 seconds, came and got me and said look at all this...pointing at what I'm assuming is bracing to stiffen the convertible...and said this is at least a 4 hour job to take all this down and then do the resonator. I told them to drop the car and I'd get it done later, because I did not have that kind of time and I didn't trust they knew what they were doing. Am I correct in assuming that the bracing is not a big deal and they should be able to replace the resonator as easily as a non-convertible? Thanks for your help.

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Our '07 is a Hard-Top Convertible (HTC) and my Midas shop did not have to touch the bracing - they did the work in under an hour.

If your shop needs to call my shop their # is (973) 579-1030 - Midas Newton NJ.

Had this done back in April - their best welder did the work - owner will know his name.

tjd24 said:

Our '07 is a Hard-Top Convertible (HTC) and my Midas shop did not have to touch the bracing - they did the work in under an hour.

If your shop needs to call my shop their # is (973) 579-1030 - Midas Newton NJ.

Had this done back in April - their best welder did the work - owner will know his name.

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Perfect! That was exactly the answer I was hoping for. I will have them call. Thank you again.

I live in the sticks where the closest Midas is like 60 miles away so I had to go to a privately owned muffler shop to get mine fixed. I showed up at 3:30PM and they put it on the lift and told me that "due to the bracing, it would take a while and they didn't have time to get to it that day and to bring it back the next day". I took it back the next morning and left it, then picked it up that evening and the labor bill was only $65, of course that was a private owned place and not a franchise. They did have to remove the bracing on mine and they actually showed me how there was no way to get to the resonator without doing so. I didn't see any way to. Mine is an 07 convertible. The price for me wasn't that bad, just an inconvenience of not having the time to wait on them, I had to get a ride to drop it off and to pick it back up.

Labor to replace resonator

It should take no more than an hour to get the bracing off and replace the resonator. There is no complex work involved. If they try to charge you for more than an hour of labor ask to know why and ask for them to show you. Unless there is rusting of bolts that would require more work to remove they are trying to rip you off and you should go somewhere else. It should cost no more than $150 for labor and the part which you can order yourself.

Thanks for the reply. That was what I suspected was the case but didn't have the info to dispute their claims. It was a Saturday and I think they were expecting a slack day and they just didn't want to bother with my car. I've found another place that will do it in the expected time frame and cost. Thanks everyone, been a great help.

x44+ said:

@slls

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.

:beer:

-jon

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Thanks, learn something new. My experience is the belt stretches so much they squeal.

Theres a defective design in the exhaust resonator. Hit a bump wrong and something inside breaks a bit and you get the whistle on acceleration and certain revs. Pay $1000+ for a new exhaust, or have a muffler guy replace the resonator with a straight pipe for $100. The first can break again, the latter is forever, and has the added benefit of giving the car a bit of a growl.

Exhaust Whistle

Thanx to everyone for helping in fixing the "whistle" on my 2006 GTP. Absolutely the resonator needed to be replaced. Had a loose baffle inside. Had the resonator cut off and replaced with a magnaflow muffler. No more whistle and it sounds just like it should. $84 total. A steal to not have that whistling noise driving me insane. I will work on the screeching brakes next. I love the car, but have to say it's a piece of junk. Sure looks nice though and fun to drive with the top down.

Replaced the resonator with the MagnaFlow 10424 this morning. 1/2 hour later and $35 in labor and it is installed and fixed. This car is finally tolerable to drive. Thank you for the advice, worked great!

Midas

tjd24 said:

Our '07 is a Hard-Top Convertible (HTC) and my Midas shop did not have to touch the bracing - they did the work in under an hour.

If your shop needs to call my shop their # is (973) 579-1030 - Midas Newton NJ.

Had this done back in April - their best welder did the work - owner will know his name.

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Ok, I am going to get my 08 Convertible fixed. Tired of this noise. Already had the entire exhaust replaced once through the dealer under warranty thank goodness. But it is back. So I need to order a Magnaflow 10424 right ? What is the best place to order from ? Will this part work on my 2008 ? Do I need to order anything else ? We have Midas here in my area. If my Midas needs to call your Midas. Who should they ask for ? Thanks in advance.

So is this what I need ?

I can get it for 60.00 right now with free shipping ? 2008 G6 GT Conv.

http://shop.advanceautoparts.com/we...ape-inlet-diameter--2-in-magnaflow_22316231-p

ConvertibleGT67 said:

I can get it for 60.00 right now with free shipping ? 2008 G6 GT Conv.

http://shop.advanceautoparts.com/we...ape-inlet-diameter--2-in-magnaflow_22316231-p

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Great price - amazon is now $73.25 with free shipping - [ame]http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=Magnaflow+10424[/ame]

As you saw in my posts this fixed the issue and hasn't come back - also note Midas took less than an hour to install so if your shop says anything different challenge it. Good luck!