Rattle for a few seconds on starting - not Tappets

[amatty]

Hi
My 1998 A4 sometimes has a rattle which sounds a bit like something touching a fan blade after I start.
This lasts for only a few seconds, after which the engine runs very quietly.
Have not managed to get out of the car fast enough to listen in the engine bay but suspect the cam chain tensioner.
Car has done 150,000 miles and runs beautifully.
Am pretty competent amateur mechanic and have done cam belt on son's 2.4 v6 and cured oil leak from under his tensioner by lifting exhaust camshaft etc and replacing tensioner gasket.
Can I replace the tensioner on my 5valve 1.8 without removing the camshafts completly if this proves to be the problem and does anybody know if there are a set of instructions on how to do this - there are a great set for changing the tensioner gasket on the V6 2.4 for instance and we did the job in about an hour !!!
Or should I just carry on and hope nothing really nasty happens?

Matty.

[amatty]

Hi
I have found a site which has a very good film of how to remove sludge in the sump filter and also how to change the camchain tensioner on a 1.8 A4. This is from America and the car is a Turbo which I gather is very prone to sludge in the filter which is generated by oil being cooked in the Turbo.
Edge Motors 1.8T oil sludge removal and camshaft adjuster replacement - YouTube

Matty

[drnik616]

HI dont know if its of any use to you but my 2000 A6 2.5 tdi does the same thing on start and sometimes idle and did earlier while trying to find my starting problem took me 5 minutes to work out that it was just the fan occasionally clipping the outer casing and i hope its the same for you and i know it sounds obvious but try asking someone to start the car while you stand and look/listen good luck

[amatty]

My rattle is definitly coming from the camchain between the camshafts and is some sort of problem with the tensioner.
It happens for a few seconds when the engine is hot and is then OK. It could be that the tensioner is worn after 150000 miles or that the oil filter in the sump is clogged. This clogging seems most common with turbo cars where the turbo burns the oil and creates bits of carbon which clog the filter.

I have always used good quality oil and it has been changed at the correct intervals so hope my non-turbo car does not have this problem.

[barrymorri]

I had this for about 40.000 miles and ignored until the rocker cover gained a 2 inch crack.
Oil started seeping so got it looked at.
Tensioner was naked so got it done pronto.