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BMW Coolant Expansion Tanks for BMW X Series E53 (2000-2006)

On certain models, namely E36, E46, and E90, the factory BMW expansion tank is prone to either breaking at connection points or blowing apart altogether. If you're starting to feel like your expansion tank is on borrowed time, it's probably time to replace with either a direct OE replacement, or strengthen your cooling setup with an aluminum expansion tank - we offer numerous performance upgrades for your expansion tank. Especially if you're someone who likes to track your BMW, we recommend upgrading your expansion tank to avoid ruining your track day.

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Coolant Expansion Tank - E46 (non-M), X3, X5 3.0

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T#:338020

Part#: 17117573781

In Stock at Vendor

Sale - Save 9% $ 140.99

This product was last offered at the strikethrough price on
04-01-2026

Starting at $ 127.98 USD

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Sale - Save 9%

$ 140.99

This product was last offered at the strikethrough price on
04-01-2026

Starting at $ 127.98 USD

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This coolant reservoir is for the non-M E46 3-series models from 1999-2006 (M3 takes a different expansion tank). We have found that the expansion tanks should be replaced based on age as well as condition. Expansion tanks seem to have a lifespan of less than six years before they show signs of fatigue and wear. Pre-emptively replacing the expansion tank as part of an overall maintenance plan can prevent you from getting stranded from a sudden failure later on. This is the most recent expansion tank design from Hella-Behr, the OEM supplier to BMW. It replaces the original BMW part number 17137787039.

Other items to consider replacing at the same time are the radiator cap, coolant level sensor, lower radiator hose, coolant temp sensor in the lower hose, and the hose clamps. If your car has an automatic transmission you should also replace the oil cooler thermostat in the radiator frame, which is a common source for leaks.

This coolant expansion tank fits:

1999-2006 E46 3 series - 323i, 323Ci, 325i, 325Ci, 325xi, 328i, 328Ci, 330i, 330Ci & 330xi (**no M)
2004-2008 X3 SAV - X3 2.5, X3 3.0, X3 3.0si
2000-2005 X5 SAV - X5 3.0

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Automatic Transmission Thermostat Kit

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T#:57122955

Part#: 17111438819KT2

Ships on Dec 30, 2026

$ 93.66 USD

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$ 93.66 USD

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Keeping your E53 X5 automatic transmission cool is essential for longevity and peak performance. The factory transmission thermostat circuit relies on plastic housings and o-ring seals that deteriorate over time. When the transmission thermostat fails or it's mounting assembly cracks, coolant loss follows putting your transmission at risk of overheating under load.

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Rein Coolant Expansion Tank - E46, E53, E83

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T#:402141

Part#: 17117573781

In Stock

Sale - Save 5% $ 76.39

This product was last offered at the strikethrough price on
08-31-2026

$ 72.57 USD

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Sale - Save 5%

$ 76.39

This product was last offered at the strikethrough price on
08-31-2026

$ 72.57 USD

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Includes cap and level sensor

Coolant Expansion Tank

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T#:591949

Part#: 17107514964

Back Ordered

Sale - Save 5% $ 80.99

This product was last offered at the strikethrough price on
08-31-2026

$ 76.94 USD

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Sale - Save 5%

$ 80.99

This product was last offered at the strikethrough price on
08-31-2026

$ 76.94 USD

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Includes bleeder screw

Expansion Tank

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T#:592015

Part#: 17137501959

Ships in 2 Business Days

Sale - Save 5% $ 74.99

This product was last offered at the strikethrough price on
08-31-2026

$ 71.24 USD

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Sale - Save 5%

$ 74.99

This product was last offered at the strikethrough price on
08-31-2026

$ 71.24 USD

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Includes vent screw and leveling switch

OEM Rein Expansion Tank Cap - BMW E32 E34 E36 E38 E39 E46 & More ...

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T#:340541

Part#: 17111742231

Ships in 1 Business Day

Sale - Save 5% $ 17.99

This product was last offered at the strikethrough price on
08-31-2026

$ 17.09 USD

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$ 17.99

This product was last offered at the strikethrough price on
08-31-2026

$ 17.09 USD

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This radiator expansion tank cap is used most BMW's from 1991-2006. It is a common failure item. When this item fails, it cannot hold pressure which results in your BMW overheating. If you are overhauling your coolant system, now is the time to consider preventative replacing this cap. It is also referred to as the coolant reservoir cap.

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Bremmen Coolant Bleeder Screw - BMW E30 E36 E38 E39 E46 E83 E90 Z4 ...

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T#:640140

Part#: 17111712788

Ships on Dec 2, 2026

Sale - Save 39% $ 3.99

This product was last offered at the strikethrough price on
09-02-2026

$ 2.44 USD

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Sale - Save 39%

$ 3.99

This product was last offered at the strikethrough price on
09-02-2026

$ 2.44 USD

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Plastic bleeder screw for cooling system is used to bleed air that would otherwise create an air pocket and lead to overheating. Includes o-ring seal.

Expansion Tank With Cap

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T#:46616025

Part#: EPK0138

Ships in 3 Business Days

Sale - Save 5% $ 71.99

This product was last offered at the strikethrough price on
08-31-2026

$ 68.25 USD

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Sale - Save 5%

$ 71.99

This product was last offered at the strikethrough price on
08-31-2026

$ 68.25 USD

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The coolant expansion tank allows excess coolant to flow in and out as temperatures rise and fall. Over time, repeated exposure to extreme temperature changes can cause the tank to crack, split, or break. To keep your cooling system sealed and functioning properly, any tank showing signs of damage—such as cracks, broken nipples, or compromised mounting points—should be replaced.

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BMW Expansion Tank With Cap - 17107514964

2X Entries Into Our F80 M3 Sweepstakes

T#:46616026

Part#: EPK0025

Ships in 3 Business Days

Sale - Save 6% $ 74.99

This product was last offered at the strikethrough price on
08-31-2026

$ 70.63 USD

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Sale - Save 6%

$ 74.99

This product was last offered at the strikethrough price on
08-31-2026

$ 70.63 USD

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The coolant expansion tank provides a place for excess coolant to flow as temperatures rise and fall. Because it’s exposed to constant heat cycles and pressure changes, it can eventually crack, split, or suffer damage to its nipples or mounting points. Keeping coolant properly contained within the system is essential, so if your tank shows signs of wear or damage, replacement is necessary. This direct-fit replacement installs easily and delivers the same heating and cooling performance as the factory unit. When replacing the tank, be sure to have additional coolant on hand. ECS Tuning carries a full range of vehicle-specific coolants designed to meet OEM specifications. Most German vehicles require specialized formulas—using the correct coolant will help prevent corrosion and ensure long-term reliability.

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Expansion Tank Mounting Plate

2X Entries Into Our F80 M3 Sweepstakes

T#:591946

Part#: 17101439110

Ships in 3 Business Days

Sale - Save 5% $ 80.99

This product was last offered at the strikethrough price on
08-31-2026

$ 76.94 USD

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Qty

Sale - Save 5%

$ 80.99

This product was last offered at the strikethrough price on
08-31-2026

$ 76.94 USD

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Bav Auto Coolant Expansion Tank - E53 X5, Z3 2.3 2.5i 2.8 3.0i ...

10X Entries Into Our F80 M3 Sweepstakes

T#:640497

Part#: 17107514964

In Stock

Sale - Save 50% $ 63.99

This product was last offered at the strikethrough price on
05-03-2026

$ 32.00 USD

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Sale - Save 50%

$ 63.99

This product was last offered at the strikethrough price on
05-03-2026

$ 32.00 USD

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This radiator expansion tank is used on E53 X5 4.4i and 4.6is with M62 engine, and Z3 2.3 2.5i 2.8 3.0i from 1999-2002. It is a common failure item as the plastic weakens over time and stress cracks will lead to coolant leaks. We have found that the expansion tanks should be replaced based on age as well as condition. Expansion tanks seem to have a lifespan of less than six years before they show signs of fatigue and wear. Pre-emptively replacing the expansion tank as part of an overall maintenance plan can prevent you from getting stranded from a sudden failure later on. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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BMW Coolant Expansion Tanks for BMW X Series E53 (2000-2006)

Coolant Expansion Tank - E46 (non-M), X3, X5 3.0

Automatic Transmission Thermostat Kit

Rein Coolant Expansion Tank - E46, E53, E83

Coolant Expansion Tank

Expansion Tank

OEM Rein Expansion Tank Cap - BMW E32 E34 E36 E38 E39 E46 & More ...

Bremmen Coolant Bleeder Screw - BMW E30 E36 E38 E39 E46 E83 E90 Z4 ...

Expansion Tank With Cap

BMW Expansion Tank With Cap - 17107514964

Expansion Tank Mounting Plate

Bav Auto Coolant Expansion Tank - E53 X5, Z3 2.3 2.5i 2.8 3.0i ...

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