Coolant Expansion Tank Kit, Rein - E70, F15, F85 X5M, E71, F16, F86 X6M

A new coolant expansion reservoir tank, cap, and sensor for X5, X5M, X6, X6M models spanning from 2007 thru 2018/2019. 

It is very common for this expansion tank to get brittle and crack over time, leaking coolant, causing overheating, and potentially stranding you on the side of the road. The constant hot/cold temperatures and positive pressure of the cooling system stress the plastic until eventually a crack develops. If you are replacing any other part of the cooling system in the E70 X5, F15 X5, F85 X5M, E71 X6, F16 X6, or F86 X6M, we suggest inspecting and replacing this tank as a preventative measure.

This is a kit including the tank (BMW part #17138621092), cap (BMW part #17117639021), and level sensor (BMW part #17137553919). The cap is a critical replacement part not just because it seals 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. Or the opposite - not venting pressure causing ruptures or cracks in a weak spot (such as the expansion tank). Replacement of the cap is recommended every three years to ensure optimum cooling efficiency and performance.

This is an expansion tank kit manufactured by Rein (CRP) Automotive - an original supplier to BMW for many cooling system components. As an 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.