Coolant Expansion Tank Cap, Rein - E82, F22, E9X, F3X, F10, F13, G30, F01, F02, F25, F26, G01, G02, E70, F15, G05, E71, F16, G06

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 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.

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. 

BMW Fitments:

1 Series
E82 / E88 (08-13) > 128i
E82 / E88 (08-13) > 135i
E82 / E88 (08-13) > 135is
E82 / E88 (08-13) > 1M (11-12)
2 Series
F22 / F23 (2014+) > 228i
F22 / F23 (2014+) > 228i xDrive
F22 / F23 (2014+) > 230i
F22 / F23 (2014+) > 230i xDrive
F22 / F23 (2014+) > M235i
F22 / F23 (2014+) > M235i xDrive
F22 / F23 (2014+) > M235i-Racing
F22 / F23 (2014+) > M240i
F22 / F23 (2014+) > M240i xDrive
F22 / F23 (2014+) > M240i-Racing
2 Series
F87 (2016+) > M2 Competition S55 (2019+)
F87 (2016+) > M2 N55 (2016-2018)
3 Series
E90 / E91 / E92 / E93 (06-13) > 325i
E90 / E91 / E92 / E93 (06-13) > 325xi
E90 / E91 / E92 / E93 (06-13) > 328i
E90 / E91 / E92 / E93 (06-13) > 328xi
E90 / E91 / E92 / E93 (06-13) > 330i
E90 / E91 / E92 / E93 (06-13) > 330xi
E90 / E91 / E92 / E93 (06-13) > 335d
E90 / E91 / E92 / E93 (06-13) > 335i
E90 / E91 / E92 / E93 (06-13) > 335is
E90 / E91 / E92 / E93 (06-13) > 335xi
3 Series
F30 / F31 / F34 (2012-2019) > 320i
F30 / F31 / F34 (2012-2019) > 320i xDrive
F30 / F31 / F34 (2012-2019) > 328d
F30 / F31 / F34 (2012-2019) > 328d xDrive
F30 / F31 / F34 (2012-2019) > 328i
F30 / F31 / F34 (2012-2019) > 328i xDrive
F30 / F31 / F34 (2012-2019) > 330i
F30 / F31 / F34 (2012-2019) > 330i xDrive
F30 / F31 / F34 (2012-2019) > 335i
F30 / F31 / F34 (2012-2019) > 335i xDrive
F30 / F31 / F34 (2012-2019) > 340i
F30 / F31 / F34 (2012-2019) > 340i xDrive
F30 / F31 / F34 (2012-2019) > Hybrid 3
4 Series
F32 / F33 / F36 (14-20) > 428i
F32 / F33 / F36 (14-20) > 428i xDrive
F32 / F33 / F36 (14-20) > 430i
F32 / F33 / F36 (14-20) > 430i xDrive
F32 / F33 / F36 (14-20) > 435i
F32 / F33 / F36 (14-20) > 435i xDrive
F32 / F33 / F36 (14-20) > 440i
F32 / F33 / F36 (14-20) > 440i xDrive
5 Series
F10 / F11 (11-16) > 528i N20 (2012-2016)
F10 / F11 (11-16) > 528i N52 (2011)
F10 / F11 (11-16) > 528i xDrive N20 (2012-2016)
F10 / F11 (11-16) > 535d
F10 / F11 (11-16) > 535d xDrive
F10 / F11 (11-16) > 535i
F10 / F11 (11-16) > 535i xDrive
F10 / F11 (11-16) > Hybrid 5
5 Series
G30 (2017-) > 530i
G30 (2017-) > 530i xDrive
G30 (2017-) > 540i (B58A 2017-2019)
G30 (2017-) > 540i (B58C 2020-)
G30 (2017-) > 540i xDrive (B58A 2017-2019)
G30 (2017-) > 540i xDrive (B58C 2020-)
6 Series
F12 / F13 (12-18) > 640i
7 Series
F01 / F02 (2009-2015) > 740Li
F01 / F02 (2009-2015) > 740i
7 Series
G12 (2016+) > 740i
G12 (2016+) > 740i xDrive
X1 Series
E84 X1 (2013-2015) > X1 28i
E84 X1 (2013-2015) > X1 28i xDrive
X3 Series
F25 X3 (2011-2017) > X3 sDrive28i
F25 X3 (2011-2017) > X3 xDrive28d Diesel
F25 X3 (2011-2017) > X3 xDrive28i
X3 Series
G01 X3 (2018+) > X3 M40i
G01 X3 (2018+) > X3 xDrive30i
X4 Series
F26 X4 (2015-2018) > X4 28i xDrive
F26 X4 (2015-2018) > X4 35i xDrive
F26 X4 (2015-2018) > X4 M40i xDrive
X4 Series
G02 X4 (2019+) > X4 M40i
G02 X4 (2019+) > X4 xDrive30i
X5 Series
E70 X5 (07-13) > X5 xDrive35d
X5 Series
F15 X5 (2014-2018) > X5 sDrive35i
F15 X5 (2014-2018) > X5 xDrive35d
F15 X5 (2014-2018) > X5 xDrive35i
X5 Series
G05 X5 (2019+) > X5 xDrive40i
X6 Series
F16 X6 (2015-2019) > X6 sDrive35i
F16 X6 (2015-2019) > X6 xDrive35i
Z Series
E89 Z4 (2009-2016) > Z4 sDrive28i
E89 Z4 (2009-2016) > Z4 sDrive30i
E89 Z4 (2009-2016) > Z4 sDrive35is