I have had a baddddd clunking/grinding noise in my car for about 3 weeks now. I know there are threads on here where many, many people have the same noise. It happens when I'm launching in first gear, and also when in the low rev range in second and third when throttle is applied. I thought for the life of me it was a suspension noise. I took it to the dealer and they agreed it was a suspension noise, but could find nothing wrong under inspection.

I decided to take it to the manager of the service dept at the dealership. We drove the car and I got the noise to replicate for him. He took the car onto the lift and showed me what the problem was, and many of you aren't going to believe it.

We all know our engines torque back and forth a solid 2 inches or so. He looked at my Catalytic converter, and noticed the cat housing itself was only an inch off of my swawbar while the car was on the lift. He then showed me my flexpipe...totally fucked up. The cat housing was sitting 2 inches low and to the right according to him. When the engine torqued under acceleration, the damn cat housing was slamming against the sway bar and sending that terrible vibration through the entire car. I am going to pick the car up tomorrow morning, so we will see if this truly is problem solved. Let's keep our fingers crossed as many people have described the same exact sound I was getting.

If that manager is right, I owe him a case of beers. It's refreshing to have a dealership actually give a **** about getting something right.

 

***UPDATE***

Guess that guy was right on the money. Picked the car up today and she was riding perfect again. For anyone with that bad clunking/grinding under acceleration, tell your dealer to take a look at where the cat is sitting. It solved it for me!!

 

dam but mines an auto sedan

 

transmission should make no difference. If your car is clunking under acceleration, then it can't hurt to have them look at it as an option. I had to find a guy that's a sitting member on the GM Engineering Fixed Operations Advisory Board to figure out the problem.

 

Could you feel it in the steering wheel as well.
Had that on one of my old VWs and it felt like it had something to do with the steering rack
but it was the resonator hitting due to engine mount movement and exhaust clearance as well.

 

^^I felt it in everything I touched. Gas, brake, clutch, shifter, steering wheel, it pretty much vibrated everything in the car.

 

great info!! thanks

 

hmm, you think this is only a SS/SC problem...?
cause i have weird vibrations in my car too.

 

this is very interesting.

I get the noise during take off, but mostly when i am coming to a stop from about 45mph +

Maybe it could be from down shifting?

I will Tell the tech's to look at that.