I've just bought an '02 3.0 A6 which has a distinct tappet clatter for a couple seconds at cold startup. You only hear this after it's been sitting overnight and you might not notice it on a open car lot or in a noisey shop. Is this normal? Sign of a tired engine? It only has 44,500 miles on it. Diagnosis?

thanks, John

 

its normal mate, all the oil drops to the oil pan over night so it has to be pumped round the engine on start up and when cold the noise is heard more till the engine gets up to pressure and normal operating temps, 44,500 is not run in yet its still a baby

 

try using full syntetic oil and low viscosity like 5w-30/40 or 0w-40.
you hear lifters, unless they are solid on these cars.

 

I took the car to our Audi dealership this afternoon so they can check it with a cold start in the morning first thing. Appartnely this model does not have hydraulic tappets to be noisy. They're guess is that it's a loose cam chain rattling because the hydraulic cam tensioner is malfunctioning. I'll get the news in the morning and post here.

Thanks,

John

 

Avant 80 you were basically right. There's a clatter briefly, maybe 2 seconds, and it's the timingl chain tensioner that's responsible. the chain is slack and rattles until the tensioner gets hard (!) again. There is an Audi bulletin out on this. Some examples of this nois are extreme and need attention, but mine is apparently acceptable and no worry as you said. I've relieved!

Thanks, John