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BMW Coolant Expansion Tanks for BMW Z3 (1996-2002)

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

For vehicles with production date up to 08/1998

T#:638094

Part#: 17111723520

In Stock

Sale - Save 20% $ 39.99

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

$ 31.99 USD

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Qty

Sale - Save 20%

$ 39.99

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

$ 31.99 USD

Add to Wish List

Replace your old expansion tank to prevent potential failure or leaks. Includes a brand new coolant level sensor. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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Moroso Performance Aluminum Expansion Tank - E36, Z3

For vehicles with a production date before 09/1998

T#:568887

Part#: 63791

In Stock

$ 445.99 USD

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$ 445.99 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 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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Bav Auto Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4 ...

T#:640208

Part#: 17117639022

In Stock

Sale - Save 15% $ 13.99

This product was last offered at the strikethrough price on
06-03-2026

$ 11.89 USD

Add to Wish List

Qty

Sale - Save 15%

$ 13.99

This product was last offered at the strikethrough price on
06-03-2026

$ 11.89 USD

Add to Wish List

This radiator expansion tank cap is used most BMW's from 1991-2006. It is a common failure item. When this item fails, it cannot hold pressure which results in your BMW overheating. If you are overhauling your coolant system, now is the time to consider preventative replacing this cap. It is also referred to as the coolant reservoir cap. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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BMW Coolant Expansion Tanks for BMW Z3 (1996-2002)

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

Moroso Performance Aluminum Expansion Tank - E36, Z3

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

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