What Does a Coolant Reservoir Do? - A coolant reservoir is a small plastic tank that is connected to the radiator of a car’s cooling system. Its primary function is to provide a space for excess coolant to expand and contract as the engine heats up and cools down. Keep the engine operating at a normal temperature. Part Numbers - 17138610656, 17138742975, 17139487210, 17139884859. This radiator surge tank matches the fit and function of the original part. This is NOT a genuine part, it's an aftermarket replacement part. Compatible with Select BMW Models - This radiator overflow tank is compatible with select BMW models - 2018-2020 530e, 2018-2020 530e xDrive, 2017-2019 530i, 2017-2019 530i xDrive, 2017-2019 540i, 2017-2019 540i xDrive, 2018-2019 640i xDrive Gran Turismo, 2017-2019 740e xDrive, 2016-2019 740i, 2017-2019 740i xDrive. Please check the description or enter Year / Make / Model on Amazon's Fitment Filter system to confirm your compatibility. Replacement Instruction - Turn off and cool down the car, disconnect the drain line, remove the retaining bolts and swap in the new reservoir tank. Professional installation is highly recommended. Durable and Long Lasting - This Coolant Recovery Tank is manufactured from quality materials, durable and long lasting. It is thoroughly tested to ensure optimum fit and performance on specific vehicle applications. Features -
Premium material.
Direct replacement.
Keeps the engine operating at a normal temperature.

Specifications-
Part Number: 17138610656, 17138742975, 17139487210, 17139884859.
Color: Black
Cap Included: Yes
Cap Maximum Pressure Rating: 200
Cap Type: Spring Loaded Twist
Level Sensor Included: Yes Material: Plastic

Compatible with Select BMW Models -

2018-2020 BMW 530e

2018-2020 BMW 530e xDrive

2017-2019 BMW 530i

2017-2019 BMW 530i xDrive

2017-2019 BMW 540i

2017-2019 BMW 540i xDrive

2018-2019 BMW 640i xDrive Gran Turismo

2017-2019 BMW 740e xDrive

2016-2019 BMW 740i

2017-2019 BMW 740i xDrive

Package Includes -
1 x Coolant Radiator Reservoir Tank with Sensor & Cap