Very Strange Noise From Car? S5 V8

[marshadee]

Hi All,

This weekend I've noticed a strange noise coming from the car. It sounds like something metal is rattling/banging underneath the car and only occurs when coming off the throttle and when the car is closing down. It sounds like its coming from or banging against the exhaust as the noise seems like it’s underneath the middle of the car (or around the back wheels area) but after asking a mate at kwit fit to put it on the ramps yesterday there was nothing obvious loose from the exhaust as initially I thought it was an exhaust clamp that may have come loose as that’s what it sounded like.

It's not happening all the time as something times I can't here it at all but it’s becoming quite consistent and I'm hearing it a fair bit now.

Bit of information about the car is it’s a 58 plate, s5 v8 and done just over 74k miles. This noise started Saturday evening after some hard driving in the day. (When I say hard, a friend wanted to see how good pull off was in the car which I'm now regretting).

Has anyone on here had anything similar happen?

Thanks,

 

[DAYTONA 500]

I had a similar problem years ago on a Mercedes ,it turned out to be a loose baffle inside the exhaust .

 

[marshadee]

A friend of mine did suggest this as it does only happen when off the throttle. Apparently inside the exhaust of a S5 when accelerating we have a flap that opens so I'm hoping its just that. The guy at Kwit didn’t think it was exhaust related at all after he had a drove the car, but then I'm not sure how many of these cars he sees. He thought it was to do with the wheels, drive shafts or something but then I would have thought it was do this when accelerating too?

 

[DAYTONA 500]

The noise on mine only happened at a certain amount of revs even whilst stationary and in park.

 

[marshadee]

thanks for your comments daytona, mine only seems to happen with moving/coming to a stop. when sitting and reving, doesnt seem to happen

 

[consilio]

I had the exact same symptoms on a 8P S3. It turned out to be the the rear diff / haldex unit that had basically worked itself loose from the chassis and was moving around on lift off of the throttle. Got it sorted under warranty so I don't know what the fix was.

 

[Shrek5]

On my previous A5 3.0TDi I had a similar noise, think it was a loose heat shield somewhere along the exhaust path. Can't recall if this was a problem that was positively ID'd and fixed or just checked over and "went away".

 

[marshadee]

My mechanic is lookintg at it now, hopefully it's just a loose heat shield and not diff related as that will be coming out of my pocket....

 

[marshadee]

apparently its my propshaft bearings that are causing the noise. On the plus side I've had a full service and the car is running so much better now and even a little more responsive.

Waiting for a quote on the shaft so I hope it isnt too much. going to get the current one refurb