I've got an 2002 S3 Quatrro with 75k on the clock. Recently serviced and 4 new tyres all round about 2 months ago.
Over the last week I've noticed a dull thumping/knocking sound coming from the engine bay or wheels. It's hard to locate the noise but it's upfront somewhere. It's not related to the revs, but it does seem to be related to speed (seems to comes in over 40mph but not always), although it doesnt bang at a very fast rate. The only common symptoms I have found is that the banging is practically non-existent with just me in the car, with 2 in the car it sounds a bit louder and with 3 in the car it's there all the time. It seems louder on smooth road surfaces, which is strange (probably coz you can hear whats going on!). It also tends to wave in and out, maybe dependant on hills?
To me, it sounds like the noise of tyres on rumble strips when you approach a roundabout.
Does anyone have any ideas?
A possible factors:
The other day my battery died so I got a new one, in the process stupid me dropped a 13mm socket thing down into the engine bay to the left of the battery, and it kinda fell under the battery where I cant see. It didnt land on the floor so it could be in there somewhere. I just cant see it, maybe its fallen out. Maybe this is causing the banging?
Also, since buying the car 2 months ago, the steering seems to pull to the left. Don't know if thats related.
Also, I've noticed the engine cover (that says V5 turbo) is missing a screw and is a bit loose. Not sure it would make a heavy enough sound for it to be that.
Cheers Guy, look forward to you amazing wisdom!