Rein EPT0242 Engine Coolant Reservoir - Radiator

OE-Style Coolant Reservoir for BMW

The Rein EPT0242 engine coolant reservoir is an OE-quality expansion tank built for BMW cooling systems that require a radiator-mounted reservoir without a cap. It is molded from virgin plastic to help resist cracking from repeated heat cycles and to support long service life in daily driving conditions.

Compatible with BMW 530i, 540i, 740i, 745e, 840i, and related xDrive and Gran Coupe applications, this reservoir is designed to match the original fit and function of the factory part.

Key Features

• Engine coolant reservoir / expansion tank for radiator-mounted applications
• Virgin plastic construction for improved durability versus regrind material
• Black plastic housing
• Twist-on cap design; cap not included
• Mounting brackets included for installation support
• OE-quality replacement from Rein Automotive
• Part number: EPT0242

Detailed Description

Rein EPT0242 is a direct-fit coolant expansion tank for BMW cooling systems that use a radiator-mounted reservoir without a cap. Rein builds this part to follow OE fitment and material standards, using virgin plastic to help reduce the risk of heat-cycle cracking and premature failure. The black plastic tank and included mounting brackets support a clean factory-style installation on the listed BMW 5 Series, 6 Series, 7 Series, and 8 Series applications. If you are replacing a leaking or brittle reservoir, EPT0242 provides a practical OE-style solution for restoring proper coolant storage and system operation.

This part cross-references BMW 17139846642 for the same application.

What This Part Helps Address

• Coolant leaks from a cracked or aging expansion tank
• Visible plastic deterioration from heat cycling
• Low coolant warnings caused by reservoir failure
• Loss of coolant storage capacity in the radiator cooling circuit
• Factory reservoir replacement on BMW models with no cap included

Installation Notes and Tips

Verify the vehicle uses a radiator-position coolant reservoir with no cap before ordering. Transfer or source the correct cap separately, since this reservoir is sold without a cap. Inspect hoses, seals, and adjacent cooling components during replacement, and confirm all connections are clean and properly seated before refilling and bleeding the cooling system.

Quality Assurance

Rein Automotive manufactures OE-quality expansion tanks to match or exceed the materials used in the original design. The use of virgin plastic is intended to improve durability and help the reservoir maintain reliable performance over time.

Compatible With BMW Models

• Fits 2020-2026 BMW 840i, radiator, w/o Cap
• Fits 2020-2026 BMW 840i Gran Coupe, radiator, w/o Cap
• Fits 2020-2026 BMW 840i xDrive, radiator, w/o Cap
• Fits 2020-2026 BMW 840i xDrive Gran Coupe, radiator, w/o Cap
• Fits 2018-2023 BMW 530e, radiator, w/o Cap
• Fits 2018-2023 BMW 530e xDrive, radiator, w/o Cap
• Fits 2017-2023 BMW 530i, radiator, w/o Cap
• Fits 2017-2023 BMW 530i xDrive, radiator, w/o Cap
• Fits 2017-2023 BMW 540i, radiator, w/o Cap
• Fits 2017-2023 BMW 540i xDrive, radiator, w/o Cap
• Fits 2016-2022 BMW 740i, radiator, w/o Cap
• Fits 2017-2022 BMW 740i xDrive, radiator, w/o Cap
• Fits 2020-2022 BMW 745e, radiator, w/o Cap
• Fits 2020-2022 BMW 745e xDrive, radiator, w/o Cap
• Fits 2020-2022 BMW 745Le xDrive, radiator, w/o Cap
• Fits 2018-2019 BMW 640i xDrive Gran Turismo, radiator, w/o Cap
• Fits 2017-2019 BMW 740e xDrive, radiator, w/o Cap