HELP!!!!!(tech help needed) Hissing sound after coolant tank replacement
 

Hi guys, I had to replace the coolant tank on my 2000 A6 2.7T (the old one had a crack in it). I got the the tank swopped out OK.

But when I started the car back up there was a hissing from the top right of the engine (that is where one of the return lines comes from on its way back to the tank) it sounds like air is escaping from some place. I am guessing that when I replaced the tank some air got into the system could this just be a self bleed or should I be worried?

Anyone know if there is a bleed valve on the A6 cooling system?

HELP!!
Thanks James

There is a 0.9185% chance a snake sneaked into the Audi when you were working on it and it is unhappy!

If that isn't the problem I would look for a problem with a vacuum line.

if you did replace the coolant lines correctly, then there is nothing to be worried about. just keep the engine running on idle while you observe closely the temp gauge and the engine compartment for any eventualities. i personally do not expect any. i hope you used the correct coolant.