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Genuine BMW Expansion Tank/Coolant Reservoir | 17139884859

BMW 530i, 540i, 740i, 540i xDrive, 530i xDrive, 530e, 740i xDrive, 640i xDrive Gran Turismo, 530e xDrive, 740e xDrive & more
$149.99
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$156.24
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$169.99
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P/N: 17139884859 Genuine BMW
Cross References:
  • 17138610656
  • 17138742975
  • 17138742976
  • 17139487210
  • 17139846642
Part Details:
  • Genuine BMW replacement expansion tank/coolant reservoir
  • Allows for expansion and contraction of coolant in the engine‚Äôs cooling system on BMW G30 chassis 5 Series, G32 chassis 6 Series, G12 chassis 7 Series, and G15 and G16 chassis 8 Series models with 2.0L B48 L4 and 3.0L B58 L6 engines
  • (1) per vehicle
  • Replaces cracked and leaking expansion tanks and expansion tanks that are discolored making it difficult to read coolant level in the tank
  • Requires expansion tank/coolant reservoir cap part number 94410625700
  • Fits BMW 530e 2018-2023, 530e xDrive 2018-2023, 530i 2017-2022, 530i xDrive 2017-2022, 540i 2017-2022, 540i xDrive 2017-2022, 640i GT xDrive 2018-2019, 740e xDrive 2017-2019, 740i 2016-2022, 740i xDrive 2017-2022, 745e xDrive 2020-2022, 840i 2020-2023, 840i Gran Coupe 2020-2023, 840i Gran Coupe xDrive 2020-2023, 840i xDrive 2020-2023

The expansion tank is the reservoir that holds excess coolant until needed by the engine and allows for the expansion and contraction of coolant as it heats up and cools down.

Expansion tanks are often the highest point in the cooling system of your BMW, whether attached to the radiator or set apart in the engine compartment and connected to the cooling system using a hose. This placement allows any air trapped in the cooling system to be pushed into the expansion tank, where it can escape, and allows coolant to be added to the cooling system without allowing air to enter.

Detecting a Faulty Expansion Tank

Expansion tanks fail when they can no longer hold enough air pressure to prevent the cooling system from overflowing or when they can no longer hold coolant. Expansion tanks that are not holding pressure allow the cooling pressure to release, lowering the coolant's boiling point and allowing the coolant to expand and aerate and the engine to overheat. Expansion tanks that are leaking coolant allow air to enter the cooling system instead of coolant, causing engine overheating. Steam coming from the expansion tank or coolant dripping from the expansion tank are signs that it has failed.

Failed expansion tank caps can mimic an expansion tank that does not hold pressure. Checking the expansion tank cap and replacing it may solve the problem of an expansion tank not maintaining pressure.

Replacing Your BMW Expansion Tank

Replacing an expansion tank is usually simple. With the exception of expansion tanks mounted to the radiator, crimping the hose from the expansion tank to the cooling system will allow you to unbolt, remove, and replace the expansion tank without draining and refilling the cooling system.

View more BMW Expansion Tanks.

Any Genuine brand part is obtained directly through our vehicle dealership network from your vehicle's manufacturer. This is always your best option for getting the exact same part that is being replaced and will be the latest version design.
Left = Driver side and Right = Passenger side.
All parts are priced individually unless identified as a set or kit. "Per car" notes identify how many of a given part your car has and "Left/Right or Front/Rear" notes means the part fits the left or right side of the car. These parts are still sold individually and you'll need to select the appropriate quantity if you plan to replace more than one of this item.

Frequently Viewed Together

We found 10 additional part(s) that are frequently viewed together.

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What This Genuine BMW Expansion Tank/Coolant Reservoir Fits?

Application information below is for reference only and should not be used to determine the exact vehicle fitment. Please use the "Make Sure It Fits" vehicle selection box above to determine the exact fitment and review any application notes. If you need any help determining if this part works with your vehicle, please don't hesitate to contact us.

BMW
18-20 - 530e Base, iPerformance
18-20 - 530e xDrive Base, iPerformance
17-20 - 530i
17-20 - 530i xDrive
17-20 - 540i
17-20 - 540i xDrive
18-19 - 640i xDrive Gran Turismo
17-19 - 740e xDrive iPerformance
16-20 - 740i
17-20 - 740i xDrive
20-20 - 745e xDrive
20-20 - 840i
20-20 - 840i Gran Coupe
20-20 - 840i xDrive
20-20 - 840i xDrive Gran Coupe