I've got a 2000 A4 1.8 SE Automatic. After a drive the other day I had the bonnet up ready to fill up my washer bottle,
and noticed a hissing noise coming from the battery, or somewhere between that and the brake fluid container.
There is no steam coming from anywhere and i can't see any leaks, so i just wondered if anyone knows what it might be?
Maybe something in the battery?