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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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Expansion Tank Replacement Kit
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Packaged by Turner - Corporate Logo
T#:15744017
Part#: N524ECSTNKKT-KT
In Stock
Sale - Save 21% $ 127.99

This product was last offered at the strikethrough price on
10-20-2026

$ 100.95 USD
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Sale - Save 21%
$ 127.99

This product was last offered at the strikethrough price on
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$ 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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Coolant Expansion Tank - E46 (non-M), X3, X5 3.0
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:338020
Part#: 17117573781
In Stock
Sale - Save 10% $ 137.99

This product was last offered at the strikethrough price on
08-26-2026

Starting at $ 123.98 USD
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Sale - Save 10%
$ 137.99

This product was last offered at the strikethrough price on
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Starting at $ 123.98 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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Packaged by Turner - Corporate Logo
T#:27605427
Part#: 17138677649TKT
Ships in 1 Business Day
Sale - Save 3% $ 208.99

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

$ 202.62 USD
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Sale - Save 3%
$ 208.99

This product was last offered at the strikethrough price on
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
Packaged by Turner - Corporate Logo
T#:338018
Part#: 17111723520
Ships in 1 Business Day
$ 99.99

This product was last offered at the strikethrough price on
10-22-2026

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 2
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
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

$ 460.17 USD
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Sale - Save 3%
$ 474.99

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

$ 460.17 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 1
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:15677493
Part#: 11517527910-KT
In Stock
Sale - Save 4% $ 336.99

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

$ 323.65 USD
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Sale - Save 4%
$ 336.99

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

$ 323.65 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 - E60 M5,E63 M6
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:584232
Part#: 17112283345KT
In Stock
$ 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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N52 ECS Cooling System Refresh Kit - E8x E9x
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:59440849
Part#: TWTRPMPPIEBRPRKT
In Stock
New Item
$ 665.99 USD
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Be sure your cooling system is up to the task

ECS Cooling System Refresh Kit - Level 2
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:15710821
Part#: 17137607482-KT
In Stock
Sale - Save 20% $ 917.99

This product was last offered at the strikethrough price on
10-13-2026

$ 736.19 USD
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$ 917.99

This product was last offered at the strikethrough price on
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$ 736.19 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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Cooling System Refresh Kit - Level 2
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:15744066
Part#: 11287837898-KT
Ships on Dec 18, 2026
Sale - Save 3% $ 808.99

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

$ 786.20 USD
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$ 808.99

This product was last offered at the strikethrough price on
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$ 786.20 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
Packaged by Turner - Corporate Logo
T#:42099868
Part#: 11537558523TKT
In Stock
Sale - Save 20% $ 829.99

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

$ 667.28 USD
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Sale - Save 20%
$ 829.99

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

$ 667.28 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
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:15677500
Part#: 82141467704-KT
In Stock
Sale - Save 20% $ 832.99

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

$ 669.06 USD
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$ 832.99

This product was last offered at the strikethrough price on
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$ 669.06 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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Automatic Transmission Thermostat Kit
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:57122955
Part#: 17111438819KT2
Back Ordered
New Item
Sale - Save 2% $ 93.99

This product was last offered at the strikethrough price on
10-19-2026

$ 91.86 USD
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$ 93.99

This product was last offered at the strikethrough price on
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$ 91.86 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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ECS Tuning Aluminum Coolant Bleeder Screw
10X Entries Into Our F80 M3 Sweepstakes
ECS - Corporate Logo
T#:363070
Part#: 003530ECS01A
Ships on Nov 12, 2026
Sale - Save 25% $ 35.99

This product was last offered at the strikethrough price on
06-13-2026

$ 26.99 USD
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Sale - Save 25%
$ 35.99

This product was last offered at the strikethrough price on
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$ 26.99 USD
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Replace the flimsy plastic bleeder screw used in the coolant expansion tank or in one of the cooling system hoses with this high quality, durable, aluminum bleeder screw. The stock plastic screw can deform over time due to heat or even regular use. We have even seen the head of the screw snap off, leaving the threaded body stuck in the expansion tank. This aluminum screw will help to prevent sudden failure of the bleeder screw, which can result in immediate overheating of the car.

ECS Tuning's Aluminum Coolant Bleeder Screw replaces Genuine BMW Part Number 17111712788

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ECS Exact-Fit Silicone Expansion Tank Hose - F-Chassis N55
10X Entries Into Our F80 M3 Sweepstakes
ECS - Corporate Logo
T#:37892077
Part#: 006402LA03
In Stock
$ 104.99 USD
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$ 104.99 USD
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Over time, factory rubber hoses break down and eventually fail as a result of consistent exposure to chemical-rich antifreeze and hot engine bay temperatures. While all coolant hoses are prone to failure, the expansion tank hose is especially susceptible to failure. To fix this issue, ECS has created the ultimate performance hose upgrade! Crafted from heavy-duty, fiber-reinforced silicone, this ECS Exact-Fit Silicone Expansion Tank Hose withstands higher temperatures and greater pressure than the factory rubber alternative. Engineered to resist electrochemical degradation, it’s tested for continuous operation at 250°F and over 45 psi, ensuring improved reliability, enhanced flow, and reduced turbulence. To further improve upon the factory hose design, ECS engineers developed precision-machined billet aluminum "Quick Connect" hose ends. Unlike the OEM plastic counterparts, these robust components resist heat-induced failure, ensuring long-term durability and reliability. Replaces OEM Part Numbers: 17128570061, 17128507235. Installation is straightforward: begin by removing the factory overflow hose and retaining clips. Transfer the OEM metal clips from the factory connector to the new billet fittings, then press the fittings onto the expansion tank and upper coolant hose. The included silicone hose is routed through the OEM path and securely clamped onto the billet fittings. After installation, the fittings can stay in place, only the silicone needs to be removed for future maintenance. Key Benefits: Direct OEM Fitment – Retains factory hose routing while eliminating the weaknesses of rubber construction. High-Temperature Resistance – Silicone material withstands extreme heat and chemicals for long-term durability. 2-Ply, Fiber-Reinforced Fluorosilicone Construction – Provides superior resistance to glycol-based coolant and other harsh fluids. Upgraded Billet Aluminum Quick-Connect Ends – CNC-machined from 6061-T6 aluminum with integrated O-rings, ensuring a secure, leak-free connection that won’t degrade over time. Easy Installation – Includes stainless steel clamps for a hassle-free, bolt-on upgrade.
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Burger Motorsports - Corporate Logo
T#:38621407
Part#: BMS-TCBS
Back Ordered
$ 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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BMW E9X Z4 E8X Coolant Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:402142
Part#: 17137640514
In Stock
$ 70.99

This product was last offered at the strikethrough price on
06-22-2026

$ 70.35 USD
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$ 70.35 USD
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Includes level sensor
Coolant Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:592020
Part#: 17137640515
In Stock
$ 97.99 USD
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$ 97.99 USD
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Includes level sensor

Meyle Coolant Expansion Tank - E53 X5, E46 M52/54, E83 X3
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We Price Match - Give Us A Call or Chat!
Meyle - Corporate Logo
T#:369184
Part#: 17117573781
In Stock
$ 66.99 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.

Other items to consider replacing at the same time are the radiator cap, coolant level sensor, lower radiator hose, coolant temp sensor, 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.

As a leading source of high-performance BMW parts and accessories since 1993, we at Turner Motorsport are honored to be the go-to supplier for tens of thousands of enthusiasts the world over. With over two decades of parts, service, and racing experience under our belt, we provide only quality performance and replacement parts. All of our performance parts are those we would (and do!) install and run on our own cars, as well as replacement parts that are Genuine BMW or from OEM manufacturers. We only offer parts we know you can trust to perform!

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Rein Coolant Expansion Tank - E46, E53, E83
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:402141
Part#: 17117573781
In Stock
$ 76.39 USD
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$ 76.39 USD
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Includes cap and level sensor

Moroso - Corporate Logo
T#:29666105
Part#: 63851
In Stock at Vendor
$ 488.99 USD
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The coolant expansion tank provides hot coolant with a place to travel, preventing pressure buildup within your cooling system. On many BMWs, this component is constructed from plastic. While cheap to replace and manufacture, a failed cooling tank can cause costly engine damage.

With this issue in mind, Moroso designed a high-quality replacement. Featuring TIG welded, 100% aluminum construction, this tank is sure to outperform it's factory counterpart.

Features:

Key Benefits:

Direct bolt-in replacement for stock, 2 piece plastic tank Fabricated Aluminum for strength, factory tanks fail after repeated high heat situations & age Features billet aluminum mounting tab/bleeder assembly for strength and precision No cutting of factory hoses is required and accepts the factory clip-on hose Moroso part (63324) racing radiator cap included; operates in the same pressure range as the factory cap Moroso radiator cap mounts to a billet aluminum neck that will not strip out like plastic threaded necks This aluminum tank can be polished, chromed, powder coated or left as-is

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Moroso - Corporate Logo
T#:568945
Part#: 63793
In Stock at Vendor
$ 433.99 USD
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$ 433.99 USD
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If you have ever experienced a leaking plastic BMW expansion tank you will realize the value of this aluminum version straight away. Even if a failure has not happened to you, it's easy to tell this tank is much stronger and more durable than the plastic used in the stock design. The original BMW plastic tanks suffer from leaks and failures with no warning. While being lightweight and recyclable, the design and construction of the stock tank is just not up for reliable long-term use. Moroso coolant expansion tanks are all pressure tested for guaranteed leak-free operation. Features: Direct bolt-in replacement to stock, cracked, or discolored tanks Fabricated Aluminum for strength, factory tanks fail after repeated high heat situations & age No cutting of factory hoses is required and accepts the factory clip-on hose Included is a Moroso Part No. 63324 racing radiator cap that operates in the same pressure range as the factory cap The Moroso radiator cap mounts to a billet aluminum neck that will not strip out like plastic threaded necks Easy to read slight level is included
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OEM Rein Expansion Tank - F01,F06,F10,F12,F13
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:555024
Part#: 17137647283
Ships in 1 Business Day
$ 118.99

This product was last offered at the strikethrough price on
10-22-2026

$ 77.95 USD
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$ 77.95 USD
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Replace your damaged expansion tank to prevent coolant loss or potential overheating issues.

his item fits the following BMW Chassis:
F01,F02,F06,F10,F12,F13

Fits BMW Engines including:
N54,N55,N57N

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BMW Coolant Expansion Tank - 17137642160
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:45791749
Part#: 17137642160
In Stock
$ 85.00

This product was last offered at the strikethrough price on
04-28-2026

$ 79.99 USD
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$ 79.99 USD
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Expansion tanks take constant abuse from high heat and harsh coolant, making them prone to cracking or failure over time. A damaged tank can quickly lead to overheating and serious engine damage, so replacement is critical at the first sign of trouble. Features: Direct fitment for hassle-free installation Precision-molded to OE specs for perfect sensor and hose connections Durable construction stands up to extreme heat and coolant chemicals Factory pressure-tested for reliable performance
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Coolant Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:591959
Part#: 17111741167
Ships in 1 Business Day
$ 69.99

This product was last offered at the strikethrough price on
10-22-2026

$ 54.59 USD
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$ 54.59 USD
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Plastic has a limited lifespan - replace every 80,000 miles
Coolant Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:388723
Part#: 17137823626
In Stock
$ 78.99

This product was last offered at the strikethrough price on
10-15-2026

$ 47.59 USD
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$ 47.59 USD
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Mounts towards the front of the engine bay
Expansion Tank Mounting Plate
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:402140
Part#: 17111436250
In Stock
$ 70.99

This product was last offered at the strikethrough price on
10-22-2026

$ 58.29 USD
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$ 58.29 USD
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BMW E39 Coolant Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:388645
Part#: 17111436381
In Stock at Vendor
$ 87.99 USD
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$ 87.99 USD
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BMW E39 Coolant Expansion Tank is an essential component designed to maintain the proper coolant level in your vehicle's cooling system. Manufactured with high-quality materials, this expansion tank ensures reliable performance and durability, preventing engine overheating by accommodating the expansion of coolant as it heats up. The kit includes a level sensor and cap, providing everything needed for a seamless installation. This expansion tank is specifically engineered to meet the exact specifications of your BMW E39, offering a perfect fit and optimal functionality.

  • Complete Kit: Includes level sensor and cap for easy installation.
  • High-Quality Construction: Built with durable materials for long-lasting performance.
  • Prevents Overheating: Helps manage coolant expansion, ensuring engine protection.
  • Exact Fit: Designed to meet the precise specifications of your BMW E39.
  • Enhanced Reliability: Ensures proper coolant level maintenance for optimal cooling system function.
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Rein - Corporate Logo
T#:38229110
Part#: 17138617045
Ships in 3 Business Days
$ 73.99 USD
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Charge Air Cooler Expansion Tank - Rein | BMW F22/23, F3X B48/B46 B58 is an essential component that ensures proper coolant circulation in the charge air cooling system. Acting as a reservoir, this expansion tank allows coolant to expand and contract with temperature fluctuations, preventing excessive pressure buildup. Over time, plastic tanks can become brittle due to constant exposure to heat cycles, leading to cracks and leaks. A failing tank can cause coolant loss, reducing the efficiency of the charge air cooler and leading to increased intake temperatures, which negatively impact horsepower and engine performance. Rein offers a high-quality direct replacement designed for durability and a perfect fit on BMW F22, F23, and F3X models with B48, B46, and B58 engines.

  • Maintains proper coolant circulation within the charge air cooling system
  • Prevents excessive pressure buildup caused by temperature fluctuations
  • Durable construction resists cracking and leaks for long-lasting performance
  • Direct replacement for BMW F22, F23, and F3X models with B48, B46, and B58 engines
  • Helps maintain optimal intake air temperatures, preserving horsepower and efficiency
  • OE-quality fitment ensures hassle-free installation and reliable function
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BMW Expansion Tank With Cap - 17107514964
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:46616026
Part#: EPK0025
Ships in 3 Business Days
$ 74.99 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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Rein Expansion Tank Mounting Plate - E83
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:402421
Part#: 17113400017
Ships in 1 Business Day
$ 166.99

This product was last offered at the strikethrough price on
10-20-2026

$ 63.95 USD
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$ 63.95 USD
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Secures the expansion tank to the radiator
AUTOTECKNIC - Corporate Logo
T#:39497984
Part#: BM-0803-GC
In Stock
$ 74.99 USD
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Turner Motorsport offers the AutoTecknic Dry Carbon Coolant Expansion Tank Cap Cover - Gloss Carbon as the perfect addition for BMW owners looking to elevate their engine bay’s appearance with premium materials and precision engineering.
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Rein Engine Coolant Reservoir - BMW G1X, G3X
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:52516268
Part#: EPT0274
Ships in 3 Business Days
New Item
$ 114.99 USD
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Protect your BMW investment with the Rein EPT0274 Engine Coolant Reservoir, the professional’s choice for cooling system restoration.

Rein Coolant Expansion Tank - E60, E61, E63, E64
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:402160
Part#: 17137542986
Ships in 1 Business Day
$ 82.99

This product was last offered at the strikethrough price on
10-22-2026

$ 66.09 USD
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$ 66.09 USD
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Includes fluid level sensor
Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:592015
Part#: 17137501959
Ships in 3 Business Days
$ 74.99

This product was last offered at the strikethrough price on
10-22-2026

$ 55.99 USD
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$ 55.99 USD
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Includes vent screw and leveling switch
Coolant Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:591949
Part#: 17107514964
Back Ordered
$ 80.99

This product was last offered at the strikethrough price on
10-22-2026

$ 58.95 USD
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$ 58.95 USD
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Includes bleeder screw


OEM Rein Expansion Tank - E90 335d
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:555023
Part#: 17138570079
Ships in 3 Business Days
$ 124.99

This product was last offered at the strikethrough price on
10-22-2026

$ 82.99 USD
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$ 82.99 USD
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Replace your damaged expansion tank to prevent coolant loss or potential overheating issues.


This item fits the following BMW Chassis:
E90

Fits BMW Engines including:
M57

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Rein Coolant Expansion Tank - E70
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:592030
Part#: 17138621092
In Stock at Vendor
$ 100.99

This product was last offered at the strikethrough price on
10-22-2026

$ 68.39 USD
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$ 68.39 USD
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Replace your cracked or faded tank
Moroso - Corporate Logo
T#:29666103
Part#: 63799
Ships in 1 Business Day
$ 459.99 USD
Free Shipping on orders $49 and up

The coolant expansion tank provides hot coolant with a place to travel, preventing pressure buildup within your cooling system. On many BMWs, this component is constructed from plastic. While cheap to replace and manufacture, a failed cooling tank can cause costly engine damage.

With this issue in mind, Moroso designed a high-quality replacement. Featuring TIG welded, 100% aluminum construction, this tank is sure to outperform it's factory counterpart.

Features:

Bolt-in replacement for stock cracked or discolored tanks Fabricated aluminum Features billet aluminum filler neck and integrated sight glass to monitor coolant level Can be polished, painted, powder coated or left as-is Moroso radiator cap (63320) included

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Meyle Coolant Expansion Tank - E36, E39, Z3
5X Entries Into Our F80 M3 Sweepstakes
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Meyle - Corporate Logo
T#:556111
Part#: 17111723520
Ships on Nov 16, 2026
$ 34.99 USD
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$ 34.99 USD
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Does not include cap or coolant level sensor

Rein - Corporate Logo
T#:45757470
Part#: 17125A022D6
Back Ordered
$ 35.99 USD
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$ 35.99 USD
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This hose connects the expansion tank to the radiator. If your coolant expansion tank hose is cracked or leaking, replace it early to prevent further coolant loss and eventual overheating.
Rein Expansion Tank Mounting Plate - E46, Z4
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:402139
Part#: 17111436251
Ships in 1 Business Day
$ 80.99

This product was last offered at the strikethrough price on
10-22-2026

$ 62.79 USD
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$ 62.79 USD
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Mounts to the side of the radiator for retaining the expansion tank

Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:593074
Part#: 17137601948
Ships in 3 Business Days
$ 118.99

This product was last offered at the strikethrough price on
10-22-2026

$ 84.09 USD
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$ 84.09 USD
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Cooling system expansion tank
Moroso - Corporate Logo
T#:568887
Part#: 63791
In Stock
$ 445.99

This product was last offered at the strikethrough price on
08-07-2026

$ 418.99 USD
Limited Qty Sale
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$ 445.99

This product was last offered at the strikethrough price on
08-07-2026

$ 418.99 USD
Limited Qty Sale
Free Shipping on orders $49 and up
If you have ever experienced a leaking plastic BMW expansion tank you will realize the value of this aluminum version straight away. Even if a failure has not happened to you, it's easy to tell this tank is much stronger and more durable than the plastic used in the stock design. The original BMW plastic tanks suffer from leaks and failures with no warning. While being lightweight and recyclable the design and construction of the stock tank is just not up for reliable long term use. Moroso coolant expansion tanks are all pressure tested for guaranteed leak-free operation and utilizes the stock pressure cap to prevent excessive pressure in the cooling system from blowing off a radiator hose or seal! Features: Each cooling system expansion tank includes a 1/8 in. pipe overflow fitting at neck, a 1/4 in. NPT water intake bung, and a 1/2 in. bung at the bottom for plumbing a line to the radiator Rugged 6061-T6 billet aluminum filler necks welded to tank to withstand continuous removal and installation of cap 100% pressure tested to eliminate leaks Accepts a standard-size radiator cap
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BMW Expansion Tank With Cap - 17137601948
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:46616024
Part#: EPK0141
In Stock
$ 97.99

This product was last offered at the strikethrough price on
06-01-2026

$ 87.99 USD
Limited Qty Sale
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$ 97.99

This product was last offered at the strikethrough price on
06-01-2026

$ 87.99 USD
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The coolant expansion tank provides a reservoir for excess coolant as it expands and contracts with temperature fluctuations. Constant exposure to these extreme changes can eventually cause the tank to crack or fail.
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Meyle Expansion Tank Cap
5X Entries Into Our F80 M3 Sweepstakes
We Price Match - Give Us A Call or Chat!
Meyle - Corporate Logo
T#:579357
Part#: 3148009004
In Stock
Sale - Save 40% $ 14.99

This product was last offered at the strikethrough price on
05-15-2026

$ 8.99 USD
Free Shipping on orders $49 and up
Sale - Save 40%
$ 14.99

This product was last offered at the strikethrough price on
05-15-2026

$ 8.99 USD
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Replace worn or missing pieces.
Rein Expansion Tank Cap
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:384807
Part#: 17117639021
In Stock
$ 16.99 USD
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Cap for plastic expansion tank
ECS - Corporate Logo
T#:56327169
Part#: 059178LA01
In Stock
New Item
Sale - Save 9% $ 407.99

This product was last offered at the strikethrough price on
07-23-2026

$ 369.99 USD
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Sale - Save 9%
$ 407.99

This product was last offered at the strikethrough price on
07-23-2026

$ 369.99 USD
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Gen 2 MINI R5X models (R55, R56, R57, R58, R59, R60, and R61 chassis) utilize a closed, highly pressurized cooling system to maintain optimal engine operating temperatures. At the center of this system is the factory plastic expansion tank, which is constantly exposed to high heat cycles, vibration, and chemical-laden antifreeze. Over time, heat and pressure leach the plasticizers from the original material. This degradation causes the tank to turn brittle and yellow, eventually leading to micro-fractures, splitting along the factory blow-molded center seam, or catastrophic connection failure. Because coolant loss under pressure can occur rapidly, a failing stock tank frequently leads to severe overheating issues or unexpected roadside breakdowns.

This ECS Heavy Duty Aluminum Coolant Expansion Tank directly addresses the structural vulnerabilities of the factory unit by replacing molded plastic with a fully TIG-welded 5052 and 6061 aluminum construction. Aluminum eliminates the risk of seam separation, cracking, or heat deformation, providing a permanent solution that withstands continuous pressure and heat without expanding or fatiguing. To ensure precise fitment, the tank was engineered using 3D CAD modeling for a direct, plug-and-play installation in the factory location. No cutting, drilling, or custom bracketry is required to secure the unit.

All hose barbs, bleed points, and sensor ports are CNC-machined to precise tolerances, guaranteeing a leak-free seal with factory quick-disconnect hoses. A precision-threaded cap neck ensures smooth engagement with the expansion tank cap while maintaining an airtight seal against the internal cap O-rings. To simplify routine maintenance, an integrated external sight glass and internal level tab eliminate guesswork, allowing you to check your coolant level at a glance. Finally, the heavy-duty wrinkle black powder coat protects the exterior of the tank from oxidation and engine bay heat while providing a clean, OEM+ appearance.

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Rein - Corporate Logo
T#:340541
Part#: 17111742231
In Stock
$ 17.99

This product was last offered at the strikethrough price on
10-22-2026

$ 13.69 USD
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$ 13.69 USD
Free Shipping on orders $49 and up
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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Coolant Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:17704748
Part#: 17138677649
In Stock
$ 118.99

This product was last offered at the strikethrough price on
10-04-2026

$ 106.99 USD
Limited Qty Sale
Free Shipping on orders $49 and up
$ 118.99

This product was last offered at the strikethrough price on
10-04-2026

$ 106.99 USD
Limited Qty Sale
Free Shipping on orders $49 and up