BMW Coolant Expansion Tanks

Bav Auto Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4 ...

T#:640208

Part#: 17117639022

In Stock

Sale - Save 15% $ 13.99

This product was last offered at the strikethrough price on
06-03-2026

$ 11.89 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. 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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Bav Auto Coolant Level Sensor - BMW E36 E39 M50/52 S50/52

T#:639793

Part#: 61318360855

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Sale - Save 19% $ 20.99

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

$ 16.99 USD

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$ 16.99 USD

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This is the sensor / sending unit that notifies the computer if your coolant level is low. When this fails, it can give a false indication of low coolant -- or worse, not inform you of a low coolant situation that could potentially cause overheating. 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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Bav Auto Coolant Expansion Tank - E36 E39 Z3 M50 M52 S50 S52 ...

T#:638094

Part#: 17111723520

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Sale - Save 20% $ 39.99

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

$ 31.99 USD

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Replace your old expansion tank to prevent potential failure or leaks. Includes a brand new coolant level sensor. 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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Bav Auto Coolant Expansion Tank - E53 X5, E46, E83 X3

T#:640496

Part#: 17137787039

In Stock

Sale - Save 18% $ 61.99

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

$ 50.99 USD

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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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Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Manual Trans ...

T#:638088

Part#: 17111436250

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Sale - Save 20% $ 44.99

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

$ 35.99 USD

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$ 35.99 USD

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This Bav Auto part is the mounting bracket from the radiator to the expansion tank on an E46 3 series with a Manual Transmission. 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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Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Auto Trans ...

T#:638089

Part#: 17111436251

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Sale - Save 20% $ 45.99

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

$ 36.79 USD

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This Bav Auto part is the mounting bracket from the radiator to the expansion tank on E46 3 series and E85/E86 Z4 with an Automatic Transmission. 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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Bav Auto Coolant Expansion Tank - BMW E90 335d M57 3.0L

T#:640493

Part#: 17138570079

In Stock

Sale - Save 20% $ 78.99

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

$ 63.19 USD

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$ 78.99

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Replace your damaged expansion tank to prevent coolant loss or potential overheating issues. 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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Bav Auto Coolant Expansion Tank - With Level Sensor - E70 X5, E71 X6 ...

T#:638093

Part#: 17138621092

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Sale - Save 20% $ 60.99

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

$ 48.79 USD

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Replace your old expansion tank to prevent potential failure or leaks. Includes a brand new coolant level sensor.

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

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

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

T#:27605427

Part#: 17138677649TKT

Ships in 2 Business Days

Sale - Save 4% $ 208.99

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

$ 200.88 USD

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$ 200.88 USD

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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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Expansion Tank Replacement Kit - E60 M5,E63 M6

T#:584232

Part#: 17112283345KT

Ships in 1-2 days

$ 250.99 USD

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$ 250.99 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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BMW N47 N55 Expansion Tank

T#:17704781

Part#: 17137642160

In Stock

Sale - Save 20% $ 98.99

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

$ 79.19 USD

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This product was last offered at the strikethrough price on
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$ 79.19 USD

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BMW N47 N55 Expansion Tank from Turner Motorsport is a high-quality replacement designed to address issues with cracked or damaged coolant expansion tanks. Engineered for durability and performance, this expansion tank ensures reliable cooling system function.

Durable Construction: Built to withstand high temperatures and pressure, ensuring long-term reliability.
Direct Replacement: Engineered as a precise fit for BMW N47 and N55 engines, making installation straightforward and hassle-free.
Enhanced Cooling Efficiency: Maintains optimal coolant levels and pressure for effective engine cooling.
High-Quality Materials: Manufactured from premium materials to resist cracking and leaks.

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Bav Auto Coolant Expansion Tank - E60 E61 E63 E64 M54 N52 N62 ...

T#:640491

Part#: 17137542986

Special Order: No Guaranteed ETA

Sale - Save 10% $ 54.99

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

$ 49.49 USD

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$ 54.99

This product was last offered at the strikethrough price on
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$ 49.49 USD

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This Bav Auto cooling system expansion tank/coolant reservoir is a direct replacement for the factory unit. Replace your cracked or leaking radiator expansion tank today. 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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Cooling System Refresh Kit - Level 2 - E9x, E82, E88, Z4

T#:42099868

Part#: 11537558523TKT

Back Ordered

Sale - Save 19% $ 829.99

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

$ 668.46 USD

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$ 829.99

This product was last offered at the strikethrough price on
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$ 668.46 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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Bav Auto Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4 ...

Bav Auto Coolant Level Sensor - BMW E36 E39 M50/52 S50/52

Bav Auto Coolant Expansion Tank - E36 E39 Z3 M50 M52 S50 S52 ...

Bav Auto Coolant Expansion Tank - E53 X5, E46, E83 X3

Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Manual Trans ...

Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Auto Trans ...

Bav Auto Coolant Expansion Tank - BMW E90 335d M57 3.0L

Bav Auto Coolant Expansion Tank - With Level Sensor - E70 X5, E71 X6 ...

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

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

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

Expansion Tank Replacement Kit - E60 M5,E63 M6

BMW N47 N55 Expansion Tank

Bav Auto Coolant Expansion Tank - E60 E61 E63 E64 M54 N52 N62 ...

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

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