Expansion Tank Cap, Genuine BMW - E30 M3, E28 M5

While your BMW cooling system may be considered very reliable, it's all depending on this coolant reservoir cap. This cap is not just to seal the coolant expansion tank - it regulates and maintains the pressure in the cooling system (1.4 bar). A failed cap can lower the pressure inside the system and lead to an overheating situation. Replacement of the cap is recommended every three years to ensure optimum cooling efficiency and performance. It's a simple and inexpensive preventative maintenance step.

BMW has had many different part numbers for this radiator cap over the years. This part number replaces BMW numbers 17112227683, 17111468071, 17111178283, 17111178250, 17119057011.

This is a Genuine BMW expansion tank cap with a two year warranty. Buying a Genuine part will usually be more expensive than an OEM or aftermarket brand but you are assured that it meets BMW's designs for fitment, performance, and longevity. It will also be the very latest design, incorporating any updates or revisions that an aftermarket brand typically will ignore.

BMW Fitments:

3 Series
E30 (84-91) > M3
5 Series
E28 (82-88) > M5 (87-88)