Find Parts That Fit Your Vehicle

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.
Sort By:

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
Free Shipping on orders $49 and up
Be sure your cooling system is up to the task
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
Free Shipping on orders $49 and up
Sale - Save 2%
$ 93.99

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

$ 91.86 USD
Free Shipping on orders $49 and up
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.
Show More Show Less
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
Free Shipping
Sale - Save 9%
$ 407.99

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

$ 369.99 USD
Free Shipping

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.

Show More Show Less

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
Free Shipping on orders $49 and up
Sale - Save 10%
$ 69.99

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

$ 62.99 USD
Free Shipping on orders $49 and up

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
Free Shipping on orders $49 and up
Sale - Save 6%
$ 49.99

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

$ 46.99 USD
Free Shipping on orders $49 and up
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
Free Shipping on orders $49 and up
Sale - Save 8%
$ 72.99

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

$ 67.49 USD
Free Shipping on orders $49 and up

Febi - Corporate Logo
T#:56001934
Part#: 46221
Special Order: No Guaranteed ETA
New Item
$ 19.99 USD
Free Shipping on orders $49 and up
This Febi Bilstein coolant expansion tank cap is designed to maintain the exact 1.4 bar pressure required to maximize your coolant's boiling point.
Febi - Corporate Logo
T#:56544005
Part#: 17139846642
Special Order: No Guaranteed ETA
New Item
$ 83.99 USD
Free Shipping on orders $49 and up
Protect your modern BMW from catastrophic thermal overload with the Febi Bilstein coolant expansion tank.

Febi - Corporate Logo
T#:56507814
Part#: 17137642160
Special Order: No Guaranteed ETA
New Item
$ 62.99 USD
Free Shipping on orders $49 and up
This Febi Bilstein coolant expansion tank offers OEM quality, engineered to withstand aggressive driving, high thermal loads, and pressurized environments.

Febi - Corporate Logo
T#:56544003
Part#: 17138677649
Special Order: No Guaranteed ETA
New Item
$ 82.99 USD
Free Shipping on orders $49 and up
Prevent catastrophic track-day or daily-driving overheating with this OEM-spec replacement Coolant Expansion Tank by Febi Bilstein.
Febi - Corporate Logo
T#:56544004
Part#: 17135A6A030
Special Order: No Guaranteed ETA
New Item
$ 82.99 USD
Free Shipping on orders $49 and up
This Febi Bilstein coolant expansion tank delivers the strength and exact fitment needed to keep your BMW's cooling system locked down.