Engine Coolant Reservoir for BMW Applications

Restore proper coolant expansion and recovery with this Rein engine coolant reservoir, part number EPK0242. Built from black plastic and supplied with a twist-on cap, it is a direct-fit radiator reservoir replacement for select BMW models that use the reservoir at the radiator.

Key Features

• Black plastic coolant reservoir construction
• Twist-on cap style with cap included
• Direct replacement for radiator-mounted reservoir applications
• Rein part number EPK0242
• Cross-references BMW OE part numbers 17117639020 and 17139846642 for the same application

Detailed Description

This Rein engine coolant reservoir is built for BMW cooling system service where the original tank has cracked, leaked, or no longer holds pressure correctly. The black plastic housing and included twist-on cap provide a straightforward replacement for radiator-position reservoir setups on BMW 530i, 540i, 740i, 745e, 840i, and related xDrive and Gran Coupe models. If you are searching for a BMW coolant reservoir replacement, radiator coolant expansion tank, or Rein EPK0242 for BMW 530i xDrive or BMW 840i xDrive Gran Coupe, this part matches the listed applications.

Compatible With: 2020-2026 BMW 840i, radiator; 2020-2026 BMW 840i Gran Coupe, radiator; 2020-2026 BMW 840i xDrive, radiator; 2020-2026 BMW 840i xDrive Gran Coupe, radiator; 2018-2023 BMW 530e, radiator; 2018-2023 BMW 530e xDrive, radiator; 2017-2023 BMW 530i, radiator; 2017-2023 BMW 530i xDrive, radiator; 2017-2023 BMW 540i, radiator; 2017-2023 BMW 540i xDrive, radiator; 2016-2022 BMW 740i, radiator; 2017-2022 BMW 740i xDrive, radiator; 2020-2022 BMW 745e, radiator; 2020-2022 BMW 745e xDrive, radiator; 2020-2022 BMW 745Le xDrive, radiator; 2018-2019 BMW 640i xDrive Gran Turismo, radiator; 2017-2019 BMW 740e xDrive, radiator.

What It Helps Fix

• Coolant loss from a cracked or aging reservoir
• Low coolant level warnings caused by tank leakage
• Pressure loss from a worn reservoir cap or tank seal
• Overheating concerns related to coolant expansion system failure
• Visible coolant residue around the radiator reservoir area

Installation Notes and Tips

Before installation, verify the reservoir location, cap style, and OE cross-reference numbers against the original part. This unit is for radiator-mounted applications and does not include mounting hardware or mounting brackets. Inspect hoses, clamps, and the surrounding cooling system components during replacement, then refill and bleed the system according to BMW service procedures.

Quality Assurance

Rein manufactures replacement cooling system components for OE-style service applications. Part number EPK0242 is built to match the listed BMW fitments and OE cross-reference numbers for a proper replacement selection.