i have an 98 a6,anytime i start her up i hearthis hissing sound coming from the passenger front,even when i shut it down i can still hear it from inside for about a minute until it goes away,can someone help me?

 

might be the SAI which is normal

 

sai switch? whats that

 

That is normal. I have the same sound when I first start it on a cold start.. sometimes just with the key in I hear it (with out the car running) and sometimes when I turn it off I hear it for a min or 2 then it goes away. def not a problem

 

you might wana get a clip of the noise so we can make sure it is the same sound though*

 

If it truly is a hissing noise I suspect that it would be your a/c , especially if you hear after you shut the car off , as it takes a little bit for your a/c pressure to equalize after shutdown

 

I was going to say the same. Mine does the same thing. It'll do exactly the same thing while the car is running if you turn off the a/c. Its normal.

 

ok glad to hearthat its all normal,thanks alot guys

 

Don't let these guys fool you!!

Look under the passenger seat for a little green snake.

 

always gotta be one smartass lol