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

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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
Bav Auto Coolant Expansion Tank - E36 E39 Z3 M50 M52 S50 S52 ...
For vehicles with production date up to 08/1998
10X Entries Into Our F80 M3 Sweepstakes
Bavarian Autosport - Corporate Logo
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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$ 39.99

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

$ 31.99 USD
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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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Coolant Expansion Tank
Coolant Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:591949
Part#: 17107514964
Back Ordered
Sale - Save 5% $ 80.99

This product was last offered at the strikethrough price on
08-31-2026

$ 76.94 USD
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Sale - Save 5%
$ 80.99

This product was last offered at the strikethrough price on
08-31-2026

$ 76.94 USD
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Includes bleeder screw
Bav Auto Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4
Bav Auto Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4 ...
10X Entries Into Our F80 M3 Sweepstakes
Bavarian Autosport - Corporate Logo
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
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Sale - Save 15%
$ 13.99

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

$ 11.89 USD
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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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OEM Rein Expansion Tank Cap - BMW E32 E34 E36 E38 E39 E46 & More
OEM Rein Expansion Tank Cap - BMW E32 E34 E36 E38 E39 E46 & More ...
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:340541
Part#: 17111742231
Ships in 1 Business Day
Sale - Save 5% $ 17.99

This product was last offered at the strikethrough price on
08-31-2026

$ 17.09 USD
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Sale - Save 5%
$ 17.99

This product was last offered at the strikethrough price on
08-31-2026

$ 17.09 USD
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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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BMW Expansion Tank With Cap - 17107514964
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
Sale - Save 6% $ 74.99

This product was last offered at the strikethrough price on
08-31-2026

$ 70.63 USD
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Sale - Save 6%
$ 74.99

This product was last offered at the strikethrough price on
08-31-2026

$ 70.63 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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Coolant Expansion Tank With Cap - 17111712835
Coolant Expansion Tank With Cap - 17111712835
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:46616014
Part#: EPK0012
Back Ordered
Sale - Save 8% $ 29.99

This product was last offered at the strikethrough price on
08-31-2026

$ 27.65 USD
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Sale - Save 8%
$ 29.99

This product was last offered at the strikethrough price on
08-31-2026

$ 27.65 USD
Free Shipping on orders $49 and up
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The coolant expansion tank provides a place for excess fluid as coolant expands and contracts with temperature changes. Constant exposure to these extremes can cause the tank to crack, break, or suffer damage to its nipples or mounting points. To keep your cooling system sealed and functioning properly, any damaged tank should be replaced.
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