Hi Everyone,
This is my 1st post but I am not new to Crossfires having mine almost 2 years. I have a 2004 White Limited Automatic. My problem and I have done many forum searches here but still have not found my problem. When I am accelerating from a stop but not hard I have a rattle or buzz sound coming from what sounds like the rear of the car. I found out about the TSB for the hatch latch and it was done yesterday but did not help, I tried adjusting the rubber stops, pulled them all the way down and the hatch closes fine and everything seems tight at the hatch but still has the same buzz. It only last a few seconds and mainly at about 1,500-2,500 rpm and only from low speed to about say 50 mph. Once at hwy speed I don't hear it. I placed some tape/rubber behind the rear license plate, did not help, rubber under the heat shields on each side of the tail pipes DNH, removed all the spare/flat kit stuff DNH, place some rubber under the cover where the upper tail light hits the glass DNH. I seen how the bumpers are to be adjusted but maybe I did it wrong but I can hit on various areas at the rear and under the car but nothing replicates this sound with the wind up or down. It almost sound like a glass loose/vibration type of buzz but the windows in the rear seem tight. It has been doing this for sometime but with my 3 year 36k running out soon I want done with it. I hate taking it to a dealer anyway. Can anyone shed some light on this buzz, give me another route of ideas. Thanks Mike

 

I would try to have a passenger listen and feel around for it while you drive.
Sorry I don't have any better answers as noise can be very hard to figure out on the internet.

 

i would suggest you have the tires balanced. sg3054.

 

You may want to check the plastic caps on the rear hatch lift cylinders (over the rods). One of mine was split and would spin on the rod at speeds between 40 to 50 MPH. Made quite an annoying sound. Good Luck!

 

i don't have this problem. its for roadglidemike, thanks though. sg3054

 

i had the same thing happen. so i figured out that it was the harmonics from the muffler there's nothing you can do except try to remove/replace the muffler. mine actually got better after i hit the snow bank last summer, bending/denting the muffler. but we had another x-fire on the used car lot, so i acquired a new muffler, and low and behold the noise re-appeared.

so i found another sure fire solution, I GOT RID OF THE CAR. Traded it in for the Trail Blazer SS. no more noise...

 

Hit a snow bank last summer? Wow do you live in the North Pole or Iceland? LOL!

 

It's the heat shield under the car just above the muffler... it sounds like buzzing bees and only happens at certain times because of the frequency of the exhaust tone at certain RPM's.

Quick easy fix... get some fiber glass insulation from your local HW store, remove the heat shield place a layer of insulation between the car and the heat shield and tighten the retaining nuts hard. Or you can try to tear off small pieces of insulation and stuff them between the gaps in the heat shield. Or, beat the hell out of the heat shield so it malforms it and it presses harder to the underbody.

 

Now my favorite new quote...

"...noise can be very hard to figure out on the internet."

maybe I'll put it on a t-shirt. Hmmm.

I've got the same sound - but only hear it in reverse? Strange.

 

so i'm off a few months. sue me! i meant this last winter. i'm thinking about too many things right now...

 

so there you have it, i guess that when i replaced the muffler i loosened up the heat shield... so as i said before get rid of the damn thing... jk. i loved my x-fire. it's just almost time for the lease to end and gmac paid for 4 payments. plus gms pricing is wonderful.

 

I have the exact same problem almost sounds like an aging suspension spring sound coming from the back only under load and in low rpms it does it. The dealer has never been able to pin point the source and they've adjusted the hatch looked at the wing and they feel it might the heat shield of the muffler or the styrofoam panels that reside beneath the carpeting in the trunk that flex as the car is being driven. It's frustrating and i cant think of what else it can be.

 

BULLFROG,

I am just going to drive and forget it. It does not do it that often but "I know its there". I guess thats what bothered me the most. Most of the time I got some NickelBack or other good stuff going and don't hear it anyway! LOL

Mike

 

restored2X - Just do HDDP's fix, just do it backwards!

Pat