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BMW Coolant Expansion Tanks for BMW G01 X3 xDrive30i B46 2.0L

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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OEM Rein Coolant Expansion Tank Overflow Hose - BMW G01 G02 Gen1 B46/...

For early models with the Gen1 B46/B48 engine - Not for vehicles with the later TU engines

2X Entries Into Our F80 M3 Sweepstakes

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.

OEM Rein Coolant Expansion Tank - F97 F98 G01 G02 B46 B58 S58 ...

2X Entries Into Our F80 M3 Sweepstakes

T#:39059266

Part#: 17135A6A030

In Stock

$ 86.99

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

$ 75.99 USD

Limited Qty Sale

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Qty

$ 86.99

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

$ 75.99 USD

Limited Qty Sale

Add to Wish List

Coolant expansion tanks can crack over time, especially during services where they need to be removed. Replace your tank with a brand new tank to ensure your cooling system remains leak-free.

Rein Coolant Expansion Tank - With Cap

2X Entries Into Our F80 M3 Sweepstakes

T#:53891623

Part#: 17135A6A030C

Ships in 4 Business Days

$ 99.99 USD

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$ 99.99 USD

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Replace your old brittle expansion tank

Rein Coolant Expansion Tank Kit - F97 F98 G01 G02 G05 G06 G07 - S58 B...

2X Entries Into Our F80 M3 Sweepstakes

T#:55965839

Part#: 17138610661

Ships in 4 Business Days

$ 56.99 USD

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$ 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

T#:25507167

Part#: 17138742660

Ships in 2 Business Days

$ 136.99 USD

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$ 136.99 USD

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The coolant expansion tank is essential for your vehicle, acting as a reservoir for extra fluid during temperature shifts. However, frequent exposure to extreme conditions makes it susceptible to cracks or breaks. Maintaining all coolant within the system is vital for optimal engine function. If you detect any damage, such as cracks, broken nipples, or compromised mounting points, swift replacement of the tank is necessary to uphold your vehicle's cooling system integrity.

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