Horrible noise on cold start (2006 318Ci N46)

[CitizenKane]

Hi.

This is a clip of my 2006 318Ci (N46) starting up cold (apologies I couldn't figure out how to embed):

https://youtu.be/98ALlAw-2Tc

It doesn’t make the noise on a warm startup. It also has a tendency to idle fairly rough when cold, but I’m not sure it’s related. No warning lights or anything and the last time I had it read my mechanic didn't mention any codes.

Anyone have any idea what this might be?

[helix402]

Maybe timing chain noise due to either worn/stretched chain or weak tensioner or both.

Try a new tensioner first. £30 and ten mins to fit.

[d_a_n1979]

IMO if it were the chain, the noise would be a constant slapping

I do agree it's more than likely a tensioner; but it needs to be inspected properly rather than folks guessing on a forum

[Touring442]

I'd try the tensioner first, but it could be crank related, rattling until there oil pressure builds up. They're simple to change but beware the coolant hose that goes into the head close by - it fits onto a plastic stub that will be very brittle and easy to snap off.

If a tensioner doesn't solve it, the problem will be more serious but tbh, just drive it until it sts itself.