Since new, my 2015 C7 has produced a light-to-moderate knocking sound at the left front when going over abrupt surfaces like railroad crossings or small speed bumps. Normal suspension movement will not cause it and it is sporadic even on moderate bumps. I was at the dealer last week and could produce the noise at will on some small speed bumps in their parking lot, but I'll have to make an appt. to have it checked out, and since they're 35 miles away I'd like to do some checking on my own first, as it may be something simple.

I was wondering if anyone could give some clues on what might be causing it. I haven't crawled under the car to check anything out but will soon, as I'd like to DIY rather than hassle with the dealer in another city. I think two suspects might be a loose shock or control arm bolt. Another owner reported recently that his control arm bolts were loose, and that produced clicking noises on turns.

 

Good Morning iclick,

I’m sorry to hear that your Corvette seems to be experiencing some sporadic knocking, and I understand that you’re seeking the advice of the other forum members. However, if you do decide to get this concern addressed by your dealer, I’d be more than willing to offer you additional assistance. Please don’t hesitate to send us a private message if this would be of interest to you, or if you have any questions in the meantime.

Best,

Angela O.
Chevrolet Customer Care

 

First thing they should have done is to check the torque on all LF suspension components.

Then verify alignment.

Then road test with you again.

 

Talked to the dealer SM today and he said he'd seen some sway bar link bolts that needed to be re-torqued. Didn't think about the sway bar, but it fits the tendency for the noise to occur when the left wheel moves and the right doesn't. Will be having that checked out on Thursday.

 

Had dealer inspect and found leaky shock, apparently having internal problems which was causing the noise. Said there were two part numbers showing for the base car and wasn't sure which to order, so I left there with the assurance they would figure it out, order, and contact me for another service visit.

 

I have a similar issue. Dealer did not see anything wrong and tightened all bolts last week when I was in for oil change. Noise still there on off when on bumps, pot holes etc. Kind of clunky sounds. Please provide any followup.

 

See my reply #5 above and check your shocks for any sign of leakage. My SM said mine wasn't exactly "flowing out," but leaking nonetheless. He said the lack of fluid caused an air pocket, and when hitting a sudden bump the air doesn't afford enough damping and it bottoms out, but changing the shock is the only way to be sure it is the source of the noise. It doesn't usually clunk except on quick jolts, and the small speed bumps in my dealer's parking lot are the perfect testing environment, as I can duplicate the noise every time by hitting them firmly.

 

Thanks will do. The service tech said if the tightening did fix it, the next step would be to look at the shocks. But I have to drop it off and leave it with them. Im trying to find a way to replicate it. The downtown Denver roads are pretty rough in places and it seems I starting to feel it more through the steering wheel too.

 

Like I mentioned, mine clunks when I pass over a small speed bump, probably about the same height as a 2x4. I haven't tried it on mine, but if you can generate the noise with a 2x4 take a small section (1-2') with you to the dealer. If you have any means to do it, I would try to smooth the sharp leading edge of the 2x4 before repeatedly colliding with it, although it probably wouldn't hurt the tire if you didn't.