BMW Coolant Expansion Tanks

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

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

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T#:27605427

Part#: 17138677649TKT

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Sale - Save 3% $ 208.99

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05-03-2026

$ 202.62 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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Coolant Expansion Tank - E36/E39/Z3 6 cylinder 1992-1998

10X Entries Into Our F80 M3 Sweepstakes

T#:338018

Part#: 17111723520

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$ 97.99

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

Starting at $ 63.18 USD

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Starting at $ 63.18 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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ECS Cooling System Refresh Kit - Level 1

10X Entries Into Our F80 M3 Sweepstakes

T#:15677493

Part#: 11517527910-KT

In Stock

Sale - Save 4% $ 336.99

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05-03-2026

$ 324.43 USD

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Stop the problems before they arise. If you vehicle has 80,000 miles or more, replace all of these components to ensure that your vehicle stays healthy. To keep everything in top order, continue to replace these components at 80,000 mile intervals. Water pump failure, cracked plastic housings, and expansion tank leaks will not be a concern once all these problem parts are replaced. This kit was put together by Turner including the basic parts that need replaced. Water pump with metal impeller Fan switch Thermostat and thermostat housing Sealing gaskets Expansion tank with level sensor, clamp and cap 1 Gallon Coolant Upper & lower radiator hoses

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Expansion Tank Replacement Kit

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T#:15744017

Part#: N524ECSTNKKT-KT

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Sale - Save 40% $ 166.99

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04-03-2026

$ 100.95 USD

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The coolant expansion tank in your vehicle gives additional fluid a place to go after expansion and contraction from temperature change. Because it is subjected to such drastic changes on a regular basis, it can often crack or break. You want to keep all the coolant in your vehicle in the cooling system. If your tank has experienced damage such as cracking, nipples breaking off, or mounting point damage, you will need to replace it. The kit includes: Expansion tank with level sensor URO expansion tank cap Genuine BMW expansion tank grommet Genuine BMW mounting bolts

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Expansion Tank Replacement Kit - E60 M5,E63 M6

10X Entries Into Our F80 M3 Sweepstakes

T#:584232

Part#: 17112283345KT

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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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ECS Cooling System Refresh Kit - Level 2

10X Entries Into Our F80 M3 Sweepstakes

T#:15677514

Part#: 11281706545-KT

Ships in 1 Business Day

Sale - Save 3% $ 474.99

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

$ 460.24 USD

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Stop the problems before they arise. If your BMW has 80,000 miles or more, replace all of these components to ensure that your vehicle stays healthy. Avoid water pump failure, cracked thermostat housings, and expansion tank leaks, which all lead to overheating and subsequent damage. This kit was put together by Turner for a complete cooling system service. GEBA water pump with metal impeller ECS aluminum water pump pulley Fan switch Thermostat and thermostat housing Sealing gaskets Expansion tank with level sensor, clamp and cap 1 Gallon Coolant Upper & lower radiator hoses Accessory drive belts Radiator drain plug

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ECS Cooling System Refresh Kit - Level 2

10X Entries Into Our F80 M3 Sweepstakes

T#:15710821

Part#: 17137607482-KT

Ships in 4 Business Days

Sale - Save 1% $ 781.99

This product was last offered at the strikethrough price on
04-06-2026

$ 773.25 USD

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As your mileage increases, so does wear and tear on your engine's cooling components. Cooling system components live a rough life, going through extreme temperature changes and being exposed to the elements. A cooling system failure can, and probably will leave you stranded. Included in this kit Water pump with new bolts Thermostat & housing Expansion tank with level sensor Expansion tank cap 1 Gallon of OEM Coolant Waterpump & thermostat hoses Upper and lower radiator hoses Accessory belt

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Automatic Transmission Thermostat Kit

10X Entries Into Our F80 M3 Sweepstakes

T#:57122955

Part#: 17111438819KT2

Ships on Dec 29, 2026

$ 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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Cooling System Refresh Kit - Level 2

10X Entries Into Our F80 M3 Sweepstakes

T#:15744066

Part#: 11287837898-KT

Ships on Dec 18, 2026

Sale - Save 13% $ 808.99

This product was last offered at the strikethrough price on
07-15-2026

$ 706.29 USD

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BMW has been designing notoriously failure-prone cooling systems since the late 1980s. The coolant capacity in most BMW engines is not sufficient to accommodate any driving or overheating near red zone temperatures. After the gauge reaches this critical area, it is common for thousands of dollars in damage to occur. Stop the problems before they arise. If your vehicle has 80,000 miles or more, replace all of these components to ensure that your vehicle stays healthy. To keep everything in top order, continue to replace these components at 80,000 mile intervals. Water pump failure, cracked housings, and expansion tank leaks will not be a concern once all these problem parts are replaced. Saleri water pump with metal impeller ECS aluminum water pump pulley Fan switch Vaico Q+ thermostat - made in Germany! Sealing gaskets Expansion tank with level sensor, clamp and cap 1 Gallon Coolant Upper & lower radiator hoses Accessory drive belts Radiator drain plug

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

10X Entries Into Our F80 M3 Sweepstakes

T#:42099868

Part#: 11537558523TKT

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05-03-2026

$ 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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Cooling System Refresh Kit - Level 2

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T#:15677500

Part#: 82141467704-KT

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Sale - Save 20% $ 832.99

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$ 670.24 USD

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As your mileage increases, so does wear and tear on your engine's cooling components. Cooling system components live a rough life, going through extreme temperature changes and being exposed to the elements. A cooling system failure can, and probably will leave you stranded. For automatic transmission (or DCT) vehicles only This kit includes: Thermostat with mounting hardware 1 gallon of BMW coolant Water pump with mounting hardware Primary cooling system hoses and radiator hose gasket, and bleeder screw Expansion tank with cap Accessory belt

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

10X Entries Into Our F80 M3 Sweepstakes

T#:638094

Part#: 17111723520

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Sale - Save 20% $ 39.99

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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

10X Entries Into Our F80 M3 Sweepstakes

T#:640496

Part#: 17137787039

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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 ...

10X Entries Into Our F80 M3 Sweepstakes

T#:638088

Part#: 17111436250

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Sale - Save 20% $ 44.99

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05-03-2026

$ 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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BMW N47 N55 Expansion Tank

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T#:17704781

Part#: 17137642160

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Sale - Save 20% $ 98.99

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05-03-2026

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

10X Entries Into Our F80 M3 Sweepstakes

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

10X Entries Into Our F80 M3 Sweepstakes

T#:640493

Part#: 17138570079

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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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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 ...

10X Entries Into Our F80 M3 Sweepstakes

T#:638093

Part#: 17138621092

In Stock

Sale - Save 20% $ 60.99

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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.

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

10X Entries Into Our F80 M3 Sweepstakes

T#:640208

Part#: 17117639022

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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

10X Entries Into Our F80 M3 Sweepstakes

T#:639793

Part#: 61318360855

In Stock

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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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 - E60 E61 E63 E64 M54 N52 N62 ...

10X Entries Into Our F80 M3 Sweepstakes

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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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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SELECT YOUR BMW

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

ECS Cooling System Refresh Kit - Level 1

Expansion Tank Replacement Kit

Expansion Tank Replacement Kit - E60 M5,E63 M6

ECS Cooling System Refresh Kit - Level 2

ECS Cooling System Refresh Kit - Level 2

Automatic Transmission Thermostat Kit

Cooling System Refresh Kit - Level 2

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

Cooling System Refresh Kit - Level 2

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 ...

BMW N47 N55 Expansion Tank

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 ...

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 - E60 E61 E63 E64 M54 N52 N62 ...

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