Owner reviews for expansion tank cap

Genuine BMW is best, luckily the genuine caps are affordable

I found out that he best caps for bmw are made by Vernet.

Oem 2.0 bar expansion tank cap is a liability to the cooling system usually resulting in catastrophic failures. I'm using the now recommended 1.4 bar cap, less chance of ruptured hoses & tanks. Bmw now recommends the 1.4 bar! And better peace of mind

Those leaks on your VW... looks to be the expansion tank cap not functioning properly...

i got a mahle premium line cap which instantly broke on me not releasing air causing the hoses to get squished, put on the old one and that fixed it.

They sent my friend a cap for a non-m car and it took him a while to figure out the leak was from the brand new cap.