03 A8 - Rapping at startup when cold... normal?
 

Hi Folks.... I've had my 2003 A8L since late 06, bought it CPO'd off lease.... I love the car and it's been "pretty" reliable. Every morning when I start the car (garaged) the engine makes a knocking sound for a split second until oil pressure builds up, it goes away REAL quick - it's been like this ever since I had the car. Is this normal? I've had BMW's and other high-end cars and they never did this... just curious.

Thanks
Dave
03 Audi A8L
74 Corvette L-82 Roadster

Its normal to have a little valve chatter when the engine gets a little older, you could try seafoaming the oil to free the lifters, valves etc.
Basically get a can of seafoam from a store like pepboys, autozone etc. then pour half the can into the oil fill and let the engine run for about an hour or take it for a short 20 mile drive. Change the oil and filter and see if that makes a difference.

Thanks Tech - I'm a 49 year old musclecar guy (got a 68 442 frame off in the garage now) these cars are foreign to me (pun intended...) - dumb question; what is seafoam?

Dave

Im surprised you don't know then! Its been around as long as Marvel mystery oil.
Its basically a solvent thats safe to put in the gas tank, intake, or oil. Of course it is a solvent so using too much seafoam or using it for too long could cause a problem like a spun main bearing so you want to keep it a short treatment. I also highly recommend finding a vaccum line and sucking some of it in there to clean out the intake, this will create a lot of smoke from the exhaust though. But it will increase lost horsepower.

Thanks again Tech - After my reply I googled it, wow, I'm surprised I haven't heard of it as well! Maybe us guys here in New England are sheltered!

I'll try it - thanks again!

Well done...

Dave