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 noisy shop. does this sound normal? It's a sound I associate with a tired engine.......

thanks, John

 

Hi Mate,
Sounds like a hydraulic tappet or two maybe slow to take up.... very common....

Try an oil additive from wynns designed to free up sticky hydraulic lifters or pop the rocker covers off some time and gently push each tappet down with the engine stopped... a weak tappet will feel spongy.

once identified, its your call to leave it or replace them....

I would change the cam belt and the tappets at the same time (saves double handing)

 

Mine does the same thing. It also taps when I accelarate when it's cold. A shop and a dealer I took it to couldn't find anything wrong.

 

might be the valves clinking mine do it every so often.

 

Thanks guys. I took the car to our audi dealership this afternoon so they could start it cold in the am to sus out the offending sound. Turns out this model (the 3.0 A6) does not have hydraulic tappets to be noisy. Their guess is that it's a malfuntioning bleed valve on the cam chain tensioner (the chain which runs between the two cams and provides for variable timing). The loose chain makes the noise before it re-tensions. They 'll call/ring me in the morning and I'll post the results here.

thanks,

John

 

It might also be a loose heat shield. I have heard this happens and usually only will happen when it is cold because the heat shield hasn't warmed up which makes it conform more and reduces that sound but i'm not sure just a suggestion you might want to check out before the stealership takes your hard earned dollars away

 

hmmm it definitely does have hydraulic lifters/tappets, I sure don't know where they get their information from and yes watch those dealers they will do anything but the proper job to get more cash out of you, im still going for the oil getting round the engine when in a cold start situation the chain tensioner doesnt get my vote that would be a different sound all together- just mt 2 cents worth

 

Did you change the oil for a different brand or viscosity when you obtained the car?

I have experienced problems changing to and running on synthetic brands/high performance oils where the engine is that tiny little bit 'bedded in'....

I found more often than not, that when cold the viscosity was so thin that until the engine was slightly warmed up, it would sound like a bag of nails... especially tappets etc.

Just a thought

 

sorry to get so long getting back to this issue but the diagnosis from the dealer is not tappets. They say the rattle is the cam chain (runs between the two cams and allows for varied timing) before the tensioner is up to hydraulic pressure. The dealer gave me bulletins describing the noise and said my case of it was w/in the norm.

thanks, guys

 

Yes this is normal, all the 3.0's do this on cold start...just how it is