Our 1.8TSi had an engine rebuild at about 80K miles to fix the oil consumption problem and had a new timing chain and tensioners fitted at the same time. It's now done 178K miles and has just started to make a rapid tapping/rattling noise for a second or two on cold start-up, which then disappears. If you restart the engine once it's been running there is no unusual noise. If you leave it an hour or so after it's been running the noise will reappear.

 

My unsophisticated diagnosis of this is that it's likely to be the camchain and tensioner, not least since the noise is very audible at the sprocket end of the cylinder head.

 

My question is - is this likely to be a correct diagnosis or is there anything else we should be checking before replacing the chain and tensioner assembly?

I've not listened specifically to a worn Octy cam chain but in my general experience worn cam chains 'rustle' rather than rattle.  Your random tapping noise could be tappet-related instead.

 

There are a number of threads on here regarding worn cam chains so a forum search would be of interest.

Edited 22 July, 20223 yr by MikeTheThinker

Thank you for the replies. I did search but didn't find anything regarding diagnosis but my local independent has confirmed that he can hook it up to his diagnostic equipment and, from what I understand. a stretched chain will show up in terms of the relative timing of the camshafts and the crankshaft, which seems logical.

Need a recording. Another 100k miles could be the sort of duration where you are talking chain stretch/ wear again and therefore the tensioner becomes fully extended.

 

Only things you can really check without pulling the timing cover is the measuring block for timing adaption and the inspection hole for the tensioner in the Lower cover.  Access is tight though.  

On 22/07/2022 at 11:54, Porker said:

Our 1.8TSi had an engine rebuild at about 80K miles to fix the oil consumption problem and had a new timing chain and tensioners fitted at the same time. It's now done 178K miles and has just started to make a rapid tapping/rattling noise for a second or two on cold start-up, which then disappears. If you restart the engine once it's been running there is no unusual noise. If you leave it an hour or so after it's been running the noise will reappear.

 

My unsophisticated diagnosis of this is that it's likely to be the camchain and tensioner, not least since the noise is very audible at the sprocket end of the cylinder head.

 

My question is - is this likely to be a correct diagnosis or is there anything else we should be checking before replacing the chain and tensioner assembly?

 

My partners 1.4 tsi had a similar noise even post chain change, swapping the valve follower tappet out got rid of this noise. No idea if it was a placebo fix but the noise never returned. Then the car got rear ended. 😐