sirus76 b6

ok so when ever i put coolant in my reservoir it leaks out after i drive it but it only leaks whats in the reservoir out of the pressure release cap my car dosnt show that its over heating and theres no CEL

John535is

Probably the seal on the expansion tank.
Check the expansion tank, could be a crack in it that opens up when the coolant is hot.
Check the hose connection at the expansion tank for cracks.

otherwise start with a replacement blue cap, the seals can go on them.
You can get a genuine cap for about $20, aftermarket such as Febi or IRO for about $5.
You can also just replace the rubber seal inside the cap, I think they are just a couple of dollars for genuine and cheaper for aftermarket.

For my 1.8 T the part numbers were:
Cap P/N #3B0121321 (with new seal).
Cap seal on its own P/N #1H0121687A
Expansion tank (if you find it has a crack) was P/N #8E0121403 (without cap)
The hose P/N #8E0121107G (without clips)

Diztek

ive had to replace the expansion tank 3 or 4 times in 10 years.