Rattling sound under car - heat shield?

[m3jala]

I had some work done to my rear suspension and drive train, and as part of that work I understand the dealer had to remove the exhaust. When I got the car back, it came, of course, with a new rattle. It's most pronounced accelerating uphill at low speeds, or while maintaining a speed at around 30-40 mph light on the gas, any gear. Seems to happen while the car is still on the cold side (engine perhaps already warmed up). Inside the car, the sound is as if it is coming from under the gear box or slightly in front of the gear box. It's not rod bearings, as the rattling is tied to the speed of the car, in gear or out.

I could take it back to the dealer, but considering they had my car for a whopping 28 days and considering I'm planning on getting rod bearings taken care of soon (as in I'll take it to a reputable indy and have them check the work of the dealer while at it), I wanted to get some opinions from you all here first. This sounds like heat shield rubbing against the exhaust, you all agree?

Sound comes on at acceleration uphill (5s) then at regular driving between 30-40mph (in gear at 20 sec mark, out of gear at 35-40 sec mark and then back in gear at 45-55 sec mark).

Thanks - appreciate your opinions.

[Richbot]

Not really relevant to your problem if only under accel, but I had a weird flutter intermittently at highway speeds. I thought it was coming from the front right of the windshield but a passneger put it behind him on the passenger side.

Turned out to be one of the small aero/wind deflector panels in front of the right rear wheel had come loose and it was sometimes flapping in the breeze, sometimes not. Maybe it got hit and broke a fastener, but somehow it must have rattled loose over time or something. New side skirt fastener and plastic pop rivet and all is well

So yeah, check and make sure all the plastic pieces of the underbody cladding are tight. There are a lot of them.

[m3jala]

Thanks for posting that. While I am pretty sure mine is heat shield or something similar it's definitely a good call out!

[dbyrd]

I don't know what kind of exhaust you have, but many after-market exhausts develop a rattle near the primary cats if the heat shield isn't hammered. See this video starting at around 2 minutes.

Either way, your rod bearing mechanic should be able to identify the problem.

[m3jala]

Right on, thanks for posting.