I've had my 2000 A6 2.7T (51k miles) for about a month now.

Whenever I start the car after it has been sitting at least 1 day, I hear a weird noise for the first 30-60 seconds.


It sounds like a pump or compressor running. it starts a few seconds after the engine starts, and only seems to do it after the car has been shut off for awhile. its a deep, low sound.

any ideas what it is?

Can someone give me a technical description of what it is and why it comes on only after the car has been sitting?

very curious...thanks!

Trevor

 

Hey Trevor,

This sound is completely normal. It is the pump for the secondary air injection system, and it only runs when the engine is cold (which is why you hear it only when the engine has been off for a day). It is designed to reduce emissions by pumping air into the exhaust while the engine is cold. Once the engine starts to warm up, the pump shuts off.

 

interesting - thanks for the quick response!

 

I get the same sound on my 2000 2.7T it seems to go away when the car has been idling for a few moments and it has got up to temperature. I think it is perfectly normal
James