The coolant reservoir is attached to the radiator and the engine with hoses and is an important component of the cooling system, which holds the excess coolant fluid used to cool the engine. When a coolant expansion tank has any issues it can lead to issues that: Constantly low on coolant, coolant leaks, engine overheating. This is a non-Part Number product, accessory only! Type: Coolant Radiator Reservoir Tank Number: 17138614293, 17137649733, 17137619189 Position: Front Number of Pins: 2 Fitment: for 528i 2012-2016 F10 Series L4 2.0L Petrol N20 Turbocharged Engine for 528i xDrive 2012-2016 F10 Series L4 2.0L Petrol N20 Turbocharged Engine How to Replace: Turn off your car and allow your engine to cool down completely. Remove the bolts and the reservoir. Wrap a cloth around the hose before disconnecting it and allow the remaining coolant to flow back into the drain pan. Take out the damaged reservoir and drain the coolant off. Reinstall the coolant hose to the radiator and tighten the clamp. Connect the other end of the coolant hose to the new coolant reservoir and tighten the mounting bolts. Refill the tank with a new coolant and run the engine to check if functions well. Colour:black+white Material:ABS Package Contents: 1 x Coolant Radiator Reservoir Tank 1 x Cap Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.