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BMW Coolant Expansion Tanks

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

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:338020

Part#: 17117573781

In Stock at Vendor

Sale - Save 2% $ 140.99

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

Starting at $ 137.98 USD

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Sale - Save 2%

$ 140.99

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

Starting at $ 137.98 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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OEM Coolant Expansion Tanks Kit - F22/23 F3X B48 B58

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:27605427

Part#: 17138677649TKT

Ships on Oct 7, 2026

Sale - Save 17% $ 208.99

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

$ 173.05 USD

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Sale - Save 17%

$ 208.99

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

$ 173.05 USD

Add to Wish List

Genuine BMW expansion tanks have a bad habit of failing after a few years. This has primarily been caused by the plastic construction of the expansion tanks. After enough heat cycles, the plastic becomes brittle and can crack, causing coolant to leak out and air to enter the coolant system. If a failing expansion tank is not addressed soon enough, the coolant loss can lead to an overheating engine. This kit includes two brand new high quality expansion tanks and caps

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Coolant Expansion Tank - E36/E39/Z3 6 cylinder 1992-1998

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:338018

Part#: 17111723520

In Stock at Vendor

$ 97.99

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

Starting at $ 77.22 USD

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Starting at $ 77.22 USD

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This high quality BEHR brand expansion tank is used on M50, M52, S50 and S52 engines, and is a common failure item on all E36 3 series with 6 cylinder engines (325/328/323 and M3) 1992-1999, Z3 with 2.8 liter, MZ3 Roadster/Coupe (S52), and E39 528i from 1997-1998. BEHR was the original equipment supplier to BMW, so you know the BEHR made expansion tank will be the highest quality available. Be leary of competitors selling this part for less -- is it a BEHR? Probably not. We only carry the BEHR brand expansion tank as it is the only one we use in our own BMWs.

If you are overhauling your coolant system, now is the time to consider preventative replacing this expansion tank. These are known to go bad, causing a leak which can leave you stranded. 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.

Need a new coolant level sensor too? If your coolant level sender is bad, your on board computer will constantly display a "low coolant" message (unless your coolant is actually low...). If you're replacing your expansion tank, now is a great time to replace this failure prone sensor. If you want a new coolant level sensor, simply choose from the option below. Because there are different sensors for different year/model BMWs, please be as specific as possible when you give us your car info during checkout (model, year, production date). Thanks!

This item fits the following BMWs:
1992-1998 E36 BMW 323ic 325i 325is 325ic 328i 328is 328ic M3
1997-1998 E39 BMW 528i
1997-1998 Z3 BMW Z3 2.8
1998-2000 Z3 BMW M Roadster M Coupe (S52)

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Expansion Tank Replacement Kit - E60 M5,E63 M6

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T#:584232

Part#: 17112283345KT

In Stock

$ 249.99 USD

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$ 249.99 USD

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The expansion tank in your BMW is a vital component of the cooling system, and because of the constant abuse from heat and temperature changes, it often fails. This kit contains all of the basic items needed for a tank replacement.

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Cooling System Refresh Kit - Level 2 - E9x, E82, E88, Z4

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:42099868

Part#: 11537558523TKT

Back Ordered

Sale - Save 19% $ 829.99

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

$ 671.10 USD

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Sale - Save 19%

$ 829.99

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

$ 671.10 USD

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Keep your BMW running at the proper temperature and avoid costly engine repairs with the Cooling System Refresh Kit, the complete maintenance solution trusted by enthusiasts and professionals alike.

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Titanium Coolant Bleeder Screw Upgrade

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T#:38621407

Part#: BMS-TCBS

Back Ordered

$ 25.00 USD

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$ 25.00 USD

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Replace your fragile OEM plastic coolant bleeder screw, which is prone to cracking and failure, with a premium titanium upgrade built for strength and style under the hood. Factory plastic components weaken over time due to constant heat cycles, leading to brittleness and potential failure. Our titanium replacement delivers superior durability, being twice as strong as aluminum yet 45% lighter than steel, ensuring unmatched resilience and long-term reliability for your coolant system. More than an upgrade, it’s a must-have for engine longevity. CNC-machined from solid titanium, each screw features a laser-etched Burger Motorsports logo and is hand-burned to create unique color patterns—no two are alike. A heavy-duty replacement O-ring is included for a perfect fit.

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Expansion Tank - Aluminum - R50/R52/R53

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T#:19428667

Part#: 80-272

In Stock

$ 185.00 USD

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$ 185.00 USD

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Upgrade your Gen1 Mini Cooper & Cooper S with this high-quality coolant expansion/fill tank from Canton Racing. With a billet radiator-style neck designed to accept the Canton Racing part #81-030 pressure cap or any 30 psi radiator-style cap, this aluminum tank offers superior performance and style.

Features a billet radiator-style neck for enhanced durability
Resolves expansion tank issues with a solid, built-in mount
Eliminates worries about separating and leaking plastic tanks
Perfectly complements Canton Racing 77-272 MINI power steering tank

Ensure reliability and improve the aesthetic appeal of your engine bay with this Canton Racing Aluminum coolant expansion/fill tank for your Gen1 Mini Cooper & Cooper S.

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Expansion Tank Pressure Cap - 30 Lbs W10 W11 1.6L Engine

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:19428666

Part#: 81-030

In Stock

$ 38.00 USD

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$ 38.00 USD

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Ensure optimal performance of your Mini's cooling system with the Expansion Tank Pressure Cap - 30 Lbs W10 W11 1.6L Engine. Designed for use with Canton Racing aluminum expansion tanks or similar applications, this 30psi radiator style cap provides reliable pressure control. Keep your engine running smoothly with this essential component.

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MINI R50 to R53 Expansion Tank Aluminum Wrinkle Black & Cap - Kit ...

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T#:31390597

Part#: 80-272BLKKT

Ships on Jul 31, 2026

$ 261.00 USD

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$ 261.00 USD

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MINI R50 to R53 Expansion Tank Aluminum Wrinkle Black & Cap - Kit offers the premium quality of Canton Racing for MINI enthusiasts. This high-grade aluminum expansion tank features a sleek Wrinkle Black powder-coated finish, designed to replace the original plastic tank with ease.

Premium Quality: Made from durable aluminum with a Wrinkle Black powder-coated finish for enhanced aesthetics and longevity.
Direct Replacement: Utilizes the original mountings for a hassle-free installation, ensuring a perfect fit.
Enhanced Functionality: Upgrades from the standard plastic tank to improve both appearance and performance over time.
Kit Includes:
- Canton Racing Coolant Tank in Wrinkle Black Powdercoating
- Canton Racing Stant Tank Cap

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MINI R50 to R53 Expansion Tank / Power Steering Tank - Wrinkle Black ...

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:31423679

Part#: 80-272BLKKT1KT

Ships on Jul 31, 2026

$ 479.00 USD

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$ 479.00 USD

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MINI R50 to R53 Expansion Tank / Power Steering Tank - Wrinkle Black Aluminum is a high-quality solution designed to address both coolant expansion and power steering needs in one kit. This kit includes a billet-style expansion tank with a radiator neck that accepts the Canton Racing part #81-030 pressure cap or any 30 psi radiator cap, ensuring a secure and leak-proof seal.

Key benefits of the MINI R50 to R53 Expansion Tank / Power Steering Tank - Wrinkle Black Aluminum include:

Dual Functionality: Combines both expansion tank and power steering tank into a single, convenient kit.
Durable Construction: Made from aluminum with a wrinkle black finish, providing long-lasting performance and a sleek appearance.
Enhanced Sealing: Features a billet radiator-style neck that fits standard 30 psi radiator caps, preventing leaks and ensuring reliable operation.
Reliable Design: Eliminates the issues associated with plastic tanks, such as separation and leakage.
Complete Kit: Includes a black expansion tank, black power steering tank, and a Stant cap for easy installation.

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Expansion Tank Aluminum - Wrinkle Black R50 R52 R53

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:19428688

Part#: 80-272BLK

Ships on Jul 31, 2026

$ 223.00 USD

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$ 223.00 USD

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Upgrade your Gen1 Mini Cooper or Cooper S with the coolant expansion/fill tank featuring a billet radiator-style neck. This tank accepts the Canton Racing part #81-030 pressure cap or any 30 psi radiator-style cap. The Canton Racing Aluminum tank with Powdercoated Wrinkle Black finish not only enhances the engine bay aesthetics but also resolves expansion tank issues with its solid build and built-in mount. Say goodbye to concerns about separating and leaking plastic expansion tanks. Pair it with the Canton Racing 77-272 MINI power steering tank for a perfect combination.

Features a billet radiator-style neck
Accepts Canton Racing pressure cap or any 30 psi radiator-style cap
Enhances engine bay aesthetics with Powdercoated Wrinkle Black finish
Resolves expansion tank issues with solid build and built-in mount
Eliminates worries about separating and leaking plastic tanks
Perfect complement to Canton Racing 77-272 MINI power steering tank

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BMW Coolant Expansion Tanks

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

OEM Coolant Expansion Tanks Kit - F22/23 F3X B48 B58

Coolant Expansion Tank - E36/E39/Z3 6 cylinder 1992-1998

Expansion Tank Replacement Kit - E60 M5,E63 M6

Cooling System Refresh Kit - Level 2 - E9x, E82, E88, Z4

Titanium Coolant Bleeder Screw Upgrade

Expansion Tank - Aluminum - R50/R52/R53

Expansion Tank Pressure Cap - 30 Lbs W10 W11 1.6L Engine

MINI R50 to R53 Expansion Tank Aluminum Wrinkle Black & Cap - Kit ...

MINI R50 to R53 Expansion Tank / Power Steering Tank - Wrinkle Black ...

Expansion Tank Aluminum - Wrinkle Black R50 R52 R53

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