Coolant Expansion Tank Cap, Aftermarket - E9X M3, E60 E63 F01 E70 E71

This part is listed by BMW as BMW part number 17117639020 (17 11 7 639 020) and is described as Coolant Expansion Tank Cap (sometimes called the radiator cap, even though it's actually installed on the expansion tank). This cap is used on many models and chassis, such as the E90/E91/E92/E93 3 Series, E82/E88 1 Series, E84 X3, E70 X5 35d, E89 Z4, F22/F23 2 Series, F30/F31/F34 3 Series, F32/F33/F36 4 Series, F01/F02 7 Series, F10 5 Series, F12/F13 6 Series, F15 X5, F16 X6, F06 6 Series Gran Coupe, F25 X3, F26 X4, F80 M3, F82 M4, F87 M2, G01 X3, G02 X4, G05 X5, G12 7 Series (740i/Li), G30 5 Series, and more. 

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 (2.0 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.

This part is manufactured by an aftermarket supplier of European auto parts, including many cooling components. While not carrying OEM status, this part follows the design of the original very closely and uses similar materials. An aftermarket part may even have the same TUV approval as its OEM counterpart. The brand may even be OEM to another manufacturer besides BMW. This aftermarket brand has a two year warranty - the same as Genuine BMW and OEM brands.

This cap is used on many BMWs. Please make sure the style of cap matches that of your BMW, and check our detailed list of fitments below carefully.