S3 rattle-downpipe/cat?

[brys3]

Hi, I've had this rattle on my s3 for a while now when accelerating slowly including after changing gears, rattle lasts about a second. Now at first I thought heat shield but as far as I could see nothing was touching. I had my car serviced at my local vw garage and asked them to check it out and there response was the cat was knackered. A few days later I took it to my local ats and asked them to have a look they also blammed the cat. So as I've got a milltek cat back I've gone for a stainless decat. I fitted it this morning and guess what, rattle still there! Does anyone have any suggestions? My cam chain tensioner is making the start up rattle could this be linked or could my standard downpipe be my issue? I really don't know where to look now. Please help

 

[Sandip]

Could possibly be the heat shield vibrating

 

[brys3]

Possibly, it's just strange that it's only when in low revs accelerating slowly I'd have thought if it wasn't touching the exhaust it would have been more so when driving harder.

 

[Welly]

Hard to say without hearing the actual sound mate I'm afraid....

Any chance of capturing the sound?

Wooo Hoo, 4000 posts!

 

[danger S3]

my exhaust shield on the cat rattles slightly when at low revs and manoeuvring, i had a wee look at it and it looks like 2 or 3 of the nits have rusted off, its still held on by 2 nuts but the threads for the others have rusted away, i need to find a way of securing it again :-S

also when cold my exhaust sounds like its blowing and i think that's because the bolts on the join under the handbreak are nearly rusted to nothing (need to replace them soon)

 

[jesters3]

I have had the same issue, an annoying metalic rattle during driving and increasing with speed. Checked all the usual culprits but it came down to the propshaft. It was two things 1. the bearing was knackered and 2. the bolts were not secured. Would be worth getting your garage to check that all the bolts are securely fitted - if this does not cure the issue then the propshalf may need changing. Bear in mind my S3 had 200k miles on it so was going to happen

 

[jesters3]

Oh - check out Welly's post on the propshaft to give you some more pointers

 

[brys3]

Thanks alot guys, I'll check that propshaft, with having a de cat there is no heat shield on it so can be that but on the propshaft with it not being constant 4wd would it cause the noise when pulling off slow?

 

[brys3]

which propshaft bolts do i check?

 

[brys3]

ive tried pulling the haldex fuse out and it still makes the rattle, would that rule propshaft out or not

 

[G60DAN]

I have this metalic rattle 2 only hear it in 1st.