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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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Heavy Duty Aluminum Expansion Tank Kit - E46 M3 S54
10X Entries Into Our F80 M3 Sweepstakes
Turner Motorsport - Corporate Logo
T#:37014879
Part#: 008682LA02
In Stock
Sale - Save 20% $ 434.99

This product was last offered at the strikethrough price on
06-14-2026

$ 347.99 USD
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Sale - Save 20%
$ 434.99

This product was last offered at the strikethrough price on
06-14-2026

$ 347.99 USD
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BMWs are well-known for their problematic cooling systems, which are often a catalyst for irreversible engine damage and a hefty repair bill. The coolant expansion tank—a crucial component responsible for holding hot engine coolant under high pressure—is a common cause of cooling system issues. Unfortunately, BMW chose to manufacture the factory E46 M3 expansion tank out of plastic. After years of exposure to high coolant temperatures, ambient engine bay heat, and chemical-rich antifreeze, the plastic degrades, eventually weakening enough to fail catastrophically.

With this issue in mind, our team of BMW enthusiasts engineered the ultimate cooling system upgrade for E46 M3 owners: a heavy-duty expansion tank built to last! Crafted from durable 5052 TIG-welded aluminum, this tank resists high temperatures and pressures without degrading over time. Unlike the fragile OEM plastic tank, Turner’s design eliminates the risk of cracking, leaking, or failure. Upgrade to our Heavy Duty Aluminum Expansion Tank Kit and say goodbye to expansion tank issues for good!

To guarantee exact fitment, the upgraded tank was designed using advanced 3D CAD modeling. All bungs, nipples, and fittings are precision-machined to ensure a secure seal with factory hose ends. Unlike other aftermarket options, this tank maintains the factory coolant capacity and includes our laser-cut logo plate at the top, providing an accurate fill level. Internal baffles are incorporated to prevent fluid cavitation, eliminating air pockets in the cooling system and avoiding false coolant level warnings during spirited driving.

Engineered for high-performance builds and daily drivers alike, this expansion tank boasts a premium wrinkle black powder coat finish for a clean "OEM+" aesthetic. This tough coating not only enhances appearance but also protects against corrosion for long-term durability. The kit includes a silicone overflow hose, a high-quality level sensor, and an OE expansion tank cap, offering a complete cooling system upgrade. Avoid the risks of the factory expansion tank—upgrade your E46 M3 today and drive with confidence!

Features & Benefits:

Durable 5052 TIG-Welded Aluminum Construction: Ensures long-term reliability and eliminates expansion tank failure. Premium Wrinkle Black Powder Coat Finish: Offers an "OEM+" appearance while preventing corrosion. Factory Coolant Capacity Retention: Maintains the same coolant level as the original design. Laser-Cut Turner Logo Plate: Provides a clear and accurate fill level indicator. Internal Baffles: Prevent the introduction of air pockets during high-performance driving. Precision-Machined External Bungs and Fittings: Ensure a perfect fit for factory hose connections. Kit Includes:

Turner Motorsport Aluminum Expansion Tank Performance Silicone Coolant Overflow Hose Expansion Tank Cap Coolant Level Sensor Product Development:

Our Heavy Duty Aluminum Expansion Tank was designed, engineered, tested, and quality inspected by our Research & Development team. Our development process includes leading-edge product technology: FARO laser scanning for reverse engineering and quality inspection, SolidWorks 3D CAD modeling, rapid prototyping utilizing our in-house 3D printer, and rigorous long-term product testing.

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Turner Motorsport - Corporate Logo
T#:49787642
Part#: 050595LA03
In Stock
Sale - Save 20% $ 509.99

This product was last offered at the strikethrough price on
06-14-2026

$ 407.99 USD
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Sale - Save 20%
$ 509.99

This product was last offered at the strikethrough price on
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$ 407.99 USD
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BMWs are well-known for their problematic cooling systems, which are often the cause of irreversible engine damage and a hefty repair bill. The coolant expansion tank—a crucial component responsible for holding hot engine coolant under high pressure—is a common cause of cooling system issues. Unfortunately, BMW chose to manufacture the factory F8X expansion tank out of plastic. After years of exposure to high coolant temperatures, ambient engine bay heat, and chemical-rich antifreeze, the plastic degrades, eventually weakening enough to fail catastrophically.

With this issue in mind, our team of BMW enthusiasts engineered the ultimate cooling system upgrade for F80 M3, F82/F83 M4, and F87 M2 Competition owners: a heavy-duty expansion tank that is built to last! Crafted from durable 5052 TIG-welded aluminum, this tank resists high temperatures and pressures without degrading over time. Unlike the fragile OEM plastic tank, our design eliminates the risk of cracking, leaking, or failure. Upgrade to our Heavy Duty Aluminum Expansion Tank Kit and say goodbye to expansion tank issues for good!

To guarantee exact fitment, the upgraded tank was designed using advanced 3D CAD modeling. All bungs, nipples, and fittings are precision-machined to ensure a secure seal with factory hose ends. Unlike other aftermarket options, this tank maintains the factory coolant capacity and includes our laser-cut logo plate at the top, providing an accurate fill level. Internal baffles are incorporated to prevent fluid cavitation, eliminating air pockets in the cooling system and avoiding false coolant level warnings during spirited driving.

Engineered for high-performance builds and daily drivers alike, this expansion tank boasts a premium wrinkle black powder coat finish for a clean "OEM+" aesthetic. This tough coating not only enhances appearance but also protects against corrosion for long-term durability. The kit includes a silicone overflow hose, a high-quality level sensor, and an OE expansion tank cap, offering a complete cooling system upgrade. Avoid the risks of the factory expansion tank—upgrade your S55-equipped BMW today and drive with confidence!

Features & Benefits:

Durable 5052 TIG-Welded Aluminum Construction: Ensures long-term reliability and eliminates expansion tank failure. Premium Wrinkle Black Powder Coat Finish: Offers an "OEM+" appearance while preventing corrosion. Factory Coolant Capacity Retention: Maintains the same coolant level as the original design. Laser-Cut Turner Logo Plate: Provides a clear and accurate fill level indicator. Internal Baffles: Prevent the introduction of air pockets during high-performance driving. Precision-Machined External Bungs and Fittings: Ensure a perfect fit for factory hose connections. Proprietary Coolant Level Sensor with Wiring Harness Adapter: Provides a plug-and-play, CEL-free functionality. Kit Includes:

Turner Motorsport Aluminum Expansion Tank Performance Silicone Coolant Overflow Hose 6mm Nipple Fitting Expansion Tank Cap Coolant Level Sensor Coolant Level Sensor Wiring Harness Adapter

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Turner Motorsport - Corporate Logo
T#:12806793
Part#: 008378LA02
In Stock
Sale - Save 20% $ 479.99

This product was last offered at the strikethrough price on
06-14-2026

$ 383.99 USD
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Sale - Save 20%
$ 479.99

This product was last offered at the strikethrough price on
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$ 383.99 USD
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Our Turner Motorsport's full aluminum expansion tank was designed and engineered in house to help with the weak point in your N52/N54 cooling system. The coolant expansion tank goes through heat cycles over and over again from regular driving, it is important that your expansion tank is doing its job to retain coolant to keep your engine operating temperatures down and keep your engine bay clean. Not only is this a major upgrade but also a great maintenance item to replace. Our expansion tank was designed to fit the OEM hoses for an easy install and comes with all the upgraded items you will need for a clean install

If your BMW needs a new expansion tank, make sure this is the last expansion tank you ever need to buy. Our coolant expansion tank has a full aluminum construction and wrinkle black powder coat for durability. Expansion tank kit comes with all the accessories you need to replace your expansion tank once, and never have to worry about it again.

Product Features:

Maintains stock coolant capacity and expansion volume
Designed to maintain OE coolant elevation, preventing air pockets
Baffled tank ensures that air pockets cannot be introduced during aggressive driving and provides accurate coolant level reading
Carefully designed bleed passage prevents the introduction of air as the engine cools
Turner engraved internal fill level
TIG welded 5052 aluminum construction
All bungs are machined to fit factory hose ends
Kit contents:

Turner Aluminum Expansion Tank
Coolant level sensor
Expansion tank cap
Heavy duty bleeder screw
Flared coolant pressure release line
Hardware for installation

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Turner Motorsport Aluminum Coolant Expansion Tank Relocation Kit - E9...
10X Entries Into Our F80 M3 Sweepstakes
Compatible with hotside and coldside (OE location) intakes
Turner Motorsport - Corporate Logo
T#:568369
Part#: 021942TMS13
In Stock
Sale - Save 15% $ 815.99

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

$ 693.59 USD
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$ 815.99

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Hotside intakes are a very common modification for N54 powered BMWs. Here at Turner Motorsport, we found ourselves unsatisfied with all existing solutions to relocate the coolant expansion tank to the cold side of your engine bay, freeing up real estate on the hot side. We decided to make an end all be all solution for people looking to relocate your expansion tank that's compatible with both hotside intakes and factory location coldside intakes. All CAD designed in-house, our N54 aluminum expansion tank relocation kit allows you to seamlessly mount our new aluminum expansion tank on the cold side of your engine bay.
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S65 Heavy Duty Aluminum Expansion Tank Kit - E9x M3
10X Entries Into Our F80 M3 Sweepstakes
Turner Motorsport - Corporate Logo
T#:36981082
Part#: 054921LA02
Ships on Feb 18, 2027
Sale - Save 15% $ 458.99

This product was last offered at the strikethrough price on
06-14-2026

$ 390.99 USD
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Sale - Save 15%
$ 458.99

This product was last offered at the strikethrough price on
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$ 390.99 USD
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BMW is well-known for its problematic cooling systems, which are often a catalyst for irreversible engine damage and a hefty repair bill. The coolant expansion tank, a crucial component responsible for holding hot engine coolant under high pressure, is a common cause of cooling system issues. Unfortunately, BMW chose to manufacture the factory E90 M3 expansion tank out of plastic. After years of exposure to high coolant temperatures, ambient engine bay heat, and chemical-rich antifreeze, the plastic degrades, eventually weakening enough to fail catastrophically.

With this issue in mind, our team of BMW enthusiasts engineered the ultimate cooling system upgrade for E90 M3 owners: a heavy-duty expansion tank built to last! Crafted from durable 5052 TIG-welded aluminum, this tank resists high temperatures and pressures without degrading over time. Unlike the fragile OEM plastic tank, Turner’s design eliminates the risk of cracking, leaking, or failure. Upgrade to our Heavy Duty Aluminum Expansion Tank Kit and say goodbye to expansion tank issues for good!

To guarantee exact fitment, the upgraded tank was designed using advanced 3D CAD modeling. All bungs, nipples, and fittings are precision-machined to ensure a secure seal with factory hose ends. Unlike other aftermarket options, this tank maintains the factory coolant capacity and includes our laser-cut logo plate at the top, providing an accurate fill level. Internal baffles are incorporated to prevent fluid cavitation, eliminating air pockets in the cooling system and avoiding false coolant level warnings during spirited driving.

Engineered for high-performance builds and daily drivers alike, this expansion tank boasts a premium wrinkle black powder coat finish for a clean "OEM+" aesthetic. This tough coating not only enhances appearance but also protects against corrosion for long-term durability. The kit includes a silicone overflow hose, a high-quality level sensor, and an OE expansion tank cap, offering a complete cooling system upgrade. Avoid the risks of the factory expansion tank—upgrade your E46 M3 today and drive with confidence!

Features & Benefits:

Durable 5052 TIG-Welded Aluminum Construction: Ensures long-term reliability and eliminates expansion tank failure.
Premium Wrinkle Black Powder Coat Finish: Offers an "OEM+" appearance while preventing corrosion.
Factory Coolant Capacity Retention: Maintains the same coolant level as the original design.
Laser-Cut Turner Logo Plate: Provides a clear and accurate fill level indicator.
Internal Baffles: Prevent the introduction of air pockets during high-performance driving.
Precision-Machined External Bungs and Fittings: Ensure a perfect fit for factory hose connections.
Kit Includes:

Turner Motorsport Aluminum Expansion Tank
Performance Silicone Coolant Overflow Hose
Expansion Tank Cap
Billet coolant bleeder screw
Coolant Level Sensor
Product Development:

Our Heavy Duty Aluminum Expansion Tank was designed, engineered, tested, and quality inspected by our Research & Development team. Our development process includes leading-edge product technology: FARO laser scanning for reverse engineering and quality inspection, SolidWorks 3D CAD modeling, rapid prototyping utilizing our in-house 3D printer, and rigorous long-term product testing.

Installation:

- Click HERE for Installation Instructions -

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Silicone Expansion Tank Relocation Heater Hose
10X Entries Into Our F80 M3 Sweepstakes
Turner Motorsport - Corporate Logo
T#:21735881
Part#: 053082LA01
In Stock
Sale - Save 25% $ 75.99

This product was last offered at the strikethrough price on
06-14-2026

$ 56.99 USD
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Sale - Save 25%
$ 75.99

This product was last offered at the strikethrough price on
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$ 56.99 USD
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Upgraded or replacement silicone heater hose for our N54 expansion tank relocation kits.

60" silicone performance coolant hose featuring a molded 90-degree bend for installs with space constraints.

Features and benefits:

Constructed of 4-Ply reinforced silicone for improved durability over the failure-prone rubber hoses.
Reduced thermal conductivity
Improved resistance to ozone and UV degradation for improved performance and durability.
Turner branded

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Heavy Duty Aluminum Expansion Tank Kit - N55 E82/E88/E9X
10X Entries Into Our F80 M3 Sweepstakes
Turner Motorsport - Corporate Logo
T#:30031522
Part#: 050610LA02
In Stock
Sale - Save 25% $ 457.99

This product was last offered at the strikethrough price on
06-14-2026

$ 343.49 USD
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Sale - Save 25%
$ 457.99

This product was last offered at the strikethrough price on
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$ 343.49 USD
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BMWs are well-known for their problematic cooling systems, which are often a catalyst for irreversible engine damage and a hefty repair bill. The coolant expansion tank—a crucial component responsible for holding hot engine coolant under high pressure—is a common cause of cooling system issues. Unfortunately, BMW chose to manufacture the factory E9X N55 expansion tank out of plastic. After years of exposure to high coolant temperatures, ambient engine bay heat, and chemical-rich antifreeze, the plastic degrades, eventually weakening enough to fail catastrophically.

With this issue in mind, our team of BMW enthusiasts engineered the ultimate cooling system upgrade for E82/88 and E90/92/93 owners: a heavy-duty expansion tank built to last! Crafted from durable 5052 TIG-welded aluminum, this tank resists high temperatures and pressures without degrading over time. Unlike the fragile OEM plastic tank, Turner’s design eliminates the risk of cracking, leaking, or failure. Upgrade to our Heavy Duty Aluminum Expansion Tank Kit and say goodbye to expansion tank issues for good!

To guarantee exact fitment, the upgraded tank was designed using advanced 3D CAD modeling. All bungs, nipples, and fittings are precision-machined to ensure a secure seal with factory hose ends. Unlike other aftermarket options, this tank maintains the factory coolant capacity and includes our laser-cut logo plate at the top, providing an accurate fill level. Internal baffles are incorporated to prevent fluid cavitation, eliminating air pockets in the cooling system and avoiding false coolant level warnings during spirited driving.

Engineered for high-performance builds and daily drivers alike, this expansion tank boasts a premium wrinkle black powder coat finish for a clean "OEM+" aesthetic. This tough coating not only enhances appearance but also protects against corrosion for long-term durability. The kit includes a silicone overflow hose, a high-quality level sensor, and an OE expansion tank cap, offering a complete cooling system upgrade. Avoid the risks of the factory expansion tank—upgrade your N55-equipped BMW today and drive with confidence!

Features & Benefits:

Durable 5052 TIG-Welded Aluminum Construction: Ensures long-term reliability and eliminates expansion tank failure. Premium Wrinkle Black Powder Coat Finish: Offers an "OEM+" appearance while preventing corrosion. Factory Coolant Capacity Retention: Maintains the same coolant level as the original design. Laser-Cut Turner Logo Plate: Provides a clear and accurate fill level indicator. Internal Baffles: Prevent the introduction of air pockets during high-performance driving. Precision-Machined External Bungs and Fittings: Ensure a perfect fit for factory hose connections. Kit Includes:

Turner Motorsport Aluminum Expansion Tank Performance Silicone Coolant Overflow Hose Aluminum Coolant Bleeder Screw Ball Stud 6mm Fitting Expansion Tank Cap Coolant Level Sensor Product Development:

Our Heavy Duty Aluminum Expansion Tank was designed, engineered, tested, and quality inspected by our Research & Development team. Our development process includes leading-edge product technology: FARO laser scanning for reverse engineering and quality inspection, SolidWorks 3D CAD modeling, rapid prototyping utilizing our in-house 3D printer, and rigorous long-term product testing.

Installation:

To aid in the installation process, we've assembled a start-to-finish installation guide, including detailed instructions on removing your factory cooling expansion tank and associated components.

Click HERE for Installation Instructions

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Turner Motorsport - Corporate Logo
T#:9998526
Part#: 008348LA01BKT
Ships in 6 Business Days
Sale - Save 20% $ 423.99

This product was last offered at the strikethrough price on
06-14-2026

$ 339.19 USD
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Sale - Save 20%
$ 423.99

This product was last offered at the strikethrough price on
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$ 339.19 USD
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Our Turner Motorsport's full aluminum expansion tank was designed and engineered in house to help with the weak point in your E36 cooling system. The coolant expansion tank goes through heat cycles over and over again from regular driving, it is important that your expansion tank is doing its job to retain coolant to keep your engine operating temperatures down and keep your engine bay clean. Not only is this a major upgrade but also a great maintenance item to replace. Our expansion tank was designed to fit the OEM hoses for an easy install and comes with all the upgraded items you will need for a clean install,

If your E36 needs a new expansion tank, make sure this is the last expansion tank you ever need to buy. Our coolant expansion tank has a full aluminum construction and wrinkle black powder coat for durability. Expansion tank kit comes with all the accessories you need to replace your expansion tank once, and never have to worry about it again.

Aluminum Coolant Expansion Tank Features:

- Maintains stock coolant capacity and expansion volume

- Designed to maintain OE coolant elevation, preventing air pockets

- Baffled tank ensures that air pockets cannot be introduced during aggressive driving and provides accurate coolant level reading

- Carefully designed bleed passage prevents the introduction of air as the engine cools

- Turner engraved internal fill level

- TIG welded 5052 aluminum construction

- All bungs are machined to fit factory hose ends

Kit contents:

Turner Aluminum Expansion Tank
Coolant level sensor
Expansion tank cap
Heavy duty bleeder screw
Flared coolant pressure release line
Hardware for installation

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Turner Expansion Tank Wire Harness - E9X/ E8X N54
10X Entries Into Our F80 M3 Sweepstakes
Turner Motorsport - Corporate Logo
T#:568366
Part#: 021942TMS05
In Stock
Sale - Save 25% $ 26.99

This product was last offered at the strikethrough price on
06-14-2026

$ 20.24 USD
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$ 26.99

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$ 20.24 USD
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The E9X/ E8X N54 Expansion Tank Wire harness is perfect for those running a relocated coolant reservoir tank. This harness plugs right into the factory connector allowing you to extend the position of the sensor without the need to splice any wires.
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Turner Motorsport - Corporate Logo
T#:56327183
Part#: 060289LA02
In Stock
New Item
$ 349.99

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

$ 329.99 USD
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$ 329.99 USD
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BMWs are well-known for their problematic cooling systems, which are often the cause of irreversible engine damage and a hefty repair bill. The coolant expansion tank—a crucial component responsible for holding hot engine coolant under high pressure—is a common cause of cooling system issues. Unfortunately, BMW chose to manufacture the factory F8X expansion tank out of plastic. After years of exposure to high coolant temperatures, ambient engine bay heat, and chemical-rich antifreeze, the plastic degrades, eventually weakening enough to fail catastrophically. With this issue in mind, our team of BMW enthusiasts engineered the ultimate cooling system upgrade for F80 M3, F82/F83 M4, and F87 M2 Competition owners: a robust intercooler expansion tank that is built to last! Constructed from durable 5052 TIG-welded aluminum, this tank withstands high temperatures and pressures without deteriorating over time. Unlike the OEM molded plastic tank, this alternative is not prone to cracking, leaking, or weakening. With the Turner Motorsport Aluminum Intercooler Expansion Tank Kit, you'll never experience expansion tank failure again! Ideal for track-driven cars, this upgrade prevents catastrophic failures that cause charge-air temp spikes and limp mode due to coolant loss in a system with no level sensor. Unlike other aftermarket coolant reservoirs, this tank retains the factory coolant capacity and features a laser-cut Turner logo plate at the top of the tank to provide an exact level for filling. To guarantee exact fitment, the upgraded tank was designed using advanced 3D CAD modeling. All bungs, nipples, and fittings are precision-machined to ensure a secure seal with factory hose ends. Designed for both high-performance builds and daily drivers, the tank features a premium wrinkle black powder coat for a sleek "OEM+" look. This durable finish goes beyond style—it prevents corrosion for long-lasting reliability. Avoid the risks of the factory expansion tank—upgrade your S55-equipped BMW today and drive with confidence!
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Turner Motorsport Aluminum Coolant Expansion Tank Relocation Kit - E8...
10X Entries Into Our F80 M3 Sweepstakes
Compatible with hotside and coldside (OE location) intakes
Turner Motorsport - Corporate Logo
T#:568368
Part#: 021942TMS14
In Stock
Sale - Save 13% $ 815.99

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

$ 708.04 USD
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Hotside intakes are a very common modification for N54 powered BMWs. Here at Turner Motorsport, we found ourselves unsatisfied with all existing solutions to relocate the coolant expansion tank to the cold side of your engine bay, freeing up real estate on the hot side. We decided to make an end all be all solution for people looking to relocate your expansion tank. All CAD designed in-house, our N54 aluminum expansion tank relocation kit allows you to seamlessly mount our new aluminum expansion tank on the cold side of your engine bay, featuring an integrated power steering pump reservoir mount. During the design process, we did everything possible to ensure no air pockets could develop in the cooling system even during spirited drives. The baffled tank is all TIG welded 5052 aluminum construction, featuring a carefully designed bleed passage. We also machined all of our bungs to accept OEM hose ends, to keep the fit and finish as OE+ as possible. Keeping with this same mindset, we made sure that coolant elevation matches OE exactly, and integrated a power steering pump reservoir mount. Our aluminum expansion tank accepts the OE coolant level sensor, bleeder screw, and coolant cap, but we include new ones with this kit, as we thought you should replace them during installation. See more about these features in the list below, and if you have any additional questions please feel free to call into our staff of skilled BMW enthusiasts at 1-800-280-6966. Find our Installation Guide HERE Features and benefits: TIG welded 5052 aluminum construction, wrinkle black powder coated Utilizes factory coolant capacity and expansion volume CAD designed to retain OE coolant elevation, which prevents air pockets Baffled tank ensures that air pockets will not be created under spirited driving conditions, and ensures accurate coolant level reading Meticulously designed bleed passage prevents air pockets while the engine cools All bungs machined for factory hose end compatibility (no barb fittings!) Integrated power steering reservoir mount Kit includes Turner Motorsport aluminum expansion tank, Turner Motorsport wiring harness, all necessary hoses, hardware, OE level sensor, bleeder screw, and coolant cap This product fits the following BMWs: 2008-2013 E82 135i 2007-2013 E88 135i
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Expansion Tank Replacement Kit
10X Entries Into Our F80 M3 Sweepstakes
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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$ 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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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
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:27605427
Part#: 17138677649TKT
Ships in 1 Business Day
Sale - Save 3% $ 208.99

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$ 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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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
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$ 460.17 USD
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Sale - Save 3%
$ 474.99

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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
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$ 323.65 USD
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Sale - Save 4%
$ 336.99

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$ 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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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
10-13-2026

$ 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
07-15-2026

$ 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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$ 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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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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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
10-19-2026

$ 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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Engine Coolant Expansion Tank
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:30729009
Part#: 17138677649
In Stock
Sale - Save 12% $ 85.99

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

$ 75.59 USD
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Sale - Save 12%
$ 85.99

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

$ 75.59 USD
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Coolant Expansion Tank
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:36032353
Part#: 17111741167
In Stock
Sale - Save 15% $ 60.99

This product was last offered at the strikethrough price on
09-16-2026

$ 51.84 USD
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$ 60.99

This product was last offered at the strikethrough price on
09-16-2026

$ 51.84 USD
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Coolant Expansion Tank - 17111436381
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:36303285
Part#: 17111436381
In Stock
Sale - Save 39% $ 65.99

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

$ 40.00 USD
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Sale - Save 39%
$ 65.99

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

$ 40.00 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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Bremmen Parts - Corporate Logo
T#:640497
Part#: 17107514964
In Stock
Sale - Save 15% $ 64.99

This product was last offered at the strikethrough price on
09-16-2026

$ 55.24 USD
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Sale - Save 15%
$ 64.99

This product was last offered at the strikethrough price on
09-16-2026

$ 55.24 USD
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This radiator expansion tank is used on E53 X5 4.4i and 4.6is with M62 engine, and Z3 2.3 2.5i 2.8 3.0i from 1999-2002. It is a common failure item as the plastic weakens over time and stress cracks will lead to coolant leaks. We have found that the expansion tanks should be replaced based on age as well as condition. Expansion tanks seem to have a lifespan of less than six years before they show signs of fatigue and wear. Pre-emptively replacing the expansion tank as part of an overall maintenance plan can prevent you from getting stranded from a sudden failure later on. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.
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Coolant Expansion Tank
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:30728965
Part#: 17137823626
In Stock
Sale - Save 20% $ 47.99

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

$ 38.34 USD
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$ 47.99

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

$ 38.34 USD
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Coolant Expansion Tank W/O Cap
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:639188
Part#: 17137529273
In Stock
Sale - Save 16% $ 38.99

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

$ 32.94 USD
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Sale - Save 16%
$ 38.99

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

$ 32.94 USD
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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.
Bremmen Parts Water Pipe Connector - E83, Z4
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:1195932
Part#: 17112248409
Ships on Nov 10, 2026
Sale - Save 3% $ 31.61

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

$ 30.66 USD
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$ 31.61

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

$ 30.66 USD
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Located underneath the expansion tank

Coolant Expansion Tank Cap
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:36032339
Part#: 17117639020
In Stock
Sale - Save 20% $ 14.99

This product was last offered at the strikethrough price on
09-17-2026

$ 11.99 USD
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Sale - Save 20%
$ 14.99

This product was last offered at the strikethrough price on
09-17-2026

$ 11.99 USD
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Bremmen Parts - Corporate Logo
T#:640140
Part#: 17111712788
Ships on Dec 16, 2026
Sale - Save 39% $ 3.99

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

$ 2.44 USD
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Sale - Save 39%
$ 3.99

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

$ 2.44 USD
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Plastic bleeder screw for cooling system is used to bleed air that would otherwise create an air pocket and lead to overheating. Includes o-ring seal.

Coolant Level Sensor
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:30728984
Part#: 61311378320
In Stock
Sale - Save 56% $ 34.99

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

$ 15.29 USD
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Sale - Save 56%
$ 34.99

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

$ 15.29 USD
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Rein - Corporate Logo
T#:55965839
Part#: 17138610661
Ships in 3 Business Days
New Item
$ 56.99 USD
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Keep your ultimate driving machine cool under pressure with this replacement auxiliary expansion tank from Rein. On modern turbocharged BMWs, the secondary cooling system plays a critical role in managing intake charge air temperatures, making a solid reservoir vital for both spirited street driving and track day reliability.
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Coolant Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:57086700
Part#: 17137642158
Ships in 3 Business Days
New Item
$ 55.99 USD
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$ 55.99 USD
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The factory expansion tank is one of the most common failure points in modern BMW cooling systems, often failing along seam welds or developing micro-cracks around fluid quick-connect fittings. Replacing a degraded reservoir with this direct-fit Rein expansion tank restores pressure containment, ensures accurate coolant expansion volume, and prevents fluid loss before it turns into severe engine damage.
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Rein Coolant Expansion Tank - With Cap
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:53891623
Part#: 17135A6A030C
Ships in 3 Business Days
New Item
$ 99.99 USD
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Replace your old brittle expansion tank


Rein - Corporate Logo
T#:55965843
Part#: 171386106612
Ships in 3 Business Days
New Item
$ 49.99 USD
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Keep your ultimate driving machine cool under pressure with this replacement auxiliary expansion tank from Rein. On modern turbocharged BMWs, the secondary cooling system plays a critical role in managing intake charge air temperatures, making a solid reservoir vital for both spirited street driving and track day reliability.
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Rein - Corporate Logo
T#:58782356
Part#: 17137642158K
Ships in 3 Business Days
New Item
$ 76.99 USD
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Eliminate coolant leaks with this brand new reservoir and cap kit from Rein - integrate coolant level sensor included with the coolant reservoir
Engine Coolant Expansion Tank Cap
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:59038367
Part#: 17135A1BD89
Ships in 3 Business Days
New Item
$ 9.99 USD
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$ 9.99 USD
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Coolant Expansion Tank - With Cap
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:55497428
Part#: 17137640514
Ships on Nov 10, 2026
New Item
Sale - Save 10% $ 69.99

This product was last offered at the strikethrough price on
10-08-2026

$ 62.99 USD
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Sale - Save 10%
$ 69.99

This product was last offered at the strikethrough price on
10-08-2026

$ 62.99 USD
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Coolant Expansion Tank
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:45723154
Part#: 17137642158
In Stock
Sale - Save 25% $ 67.99

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

$ 50.99 USD
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Sale - Save 25%
$ 67.99

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

$ 50.99 USD
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E30 Coolant Expansion Tank
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:57507437
Part#: 17111712641
Ships on Jan 11, 2027
New Item
Sale - Save 6% $ 49.99

This product was last offered at the strikethrough price on
10-21-2026

$ 46.99 USD
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Sale - Save 6%
$ 49.99

This product was last offered at the strikethrough price on
10-21-2026

$ 46.99 USD
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Coolant Expansion Tank
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:53044121
Part#: 17137601948
In Stock
New Item
Sale - Save 8% $ 72.99

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

$ 67.49 USD
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Sale - Save 8%
$ 72.99

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

$ 67.49 USD
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MINI F5X F6X Expansion Tank
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:28138156
Part#: 17137617362
Special Order: No Guaranteed ETA
Sale - Save 5% $ 81.99

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

$ 77.51 USD
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Sale - Save 5%
$ 81.99

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

$ 77.51 USD
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MINI F5X F6X Expansion Tank

For Mini owners looking to maintain optimal engine performance, the MINI F5X F6X Expansion Tank is an essential component. This expansion tank ensures proper cooling system functionality, preventing overheating and potential engine damage. Crafted with high-quality materials, it guarantees durability and reliability for long-term use, providing peace of mind to Mini enthusiasts.

  • Ensures proper cooling system functionality
  • Prevents overheating and potential engine damage
  • Crafted with high-quality materials for durability
  • Provides peace of mind to Mini enthusiasts
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