Hi, I bought a 2005 Audi A4 (convertible) 1.8 turbo, a few weeks ago. Since a week ago, every time I start the car there’s a loud noise that comes from the engine (it’s not cold outside). When I turn the car off and start it again the sound goes away. I haven’t has an Audi before and I don’t know what’s wrong with it.

 

does it stop after about 30seconds to a minute? do you have a check engine light? usually loud startup noises that go away have to do with the secondary air pump and either a split line or a failing pump, the pumps on the passenger side of the car behind the passenger side fog light grille

 

The sound does not stop until i restart the car. The check engine light is not on. Looks like i have to take it for a check.