Failed N55 Expansion Tank

[mr.fabulous]

Looks like my expansion tank has failed (leaking around the top seam). Anybody ever replace theirs? Do the clips re-use or do I need those too? Any advice will help.

[OneWhite35]

I replaced mine this summer due to the same leak around the seam.

All you need to buy is a replacement expansion tank and additional coolant. Everything else, including the clips, hoses, cap, and bleeder screw can be reused. The coolant level sensor can be reused too but I don't think you can buy the tank without the sensor already included inside.

Note that BMW revised some of the parts over the years. I suggest you get the latest version of the expansion tank and bleeder screw.

Also, don't forget to run through the coolant bleeding procedure (you can the instructions for this on the forums - it's super easy) afterwards to remove air bubbles from the system.

[mr.fabulous]

Got a Lyft to and from the dealer; $150 for the tank, $50 for Lyft. Easiest thing in the world to replace... and listening to the car bleed itself really is interesting. So far, so good.