Expansion Tank Cap, CRP - E30 325i, E34 525i M20

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. 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.

This is a radiator cap manufactured by Rein (CRP) Automotive - the original supplier to BMW for this part, as well as many other cooling system parts. As the OEM it meets all of BMW's original design, fitment, and performance requirements and is TUV approved. OEM parts are the best alternative to more expensive Original BMW parts because they are virtually identical without the inflated price tag. This part has a two year warranty.

BMW Fitments:

3 Series
E30 (84-91) > 325i
E30 (84-91) > 325is
E30 (84-91) > 325ix
5 Series
E34 (89-95) > 525i M20