Rein 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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Coolant Expansion Tank
Coolant Expansion Tank
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T#:591949
Part#: 17107514964
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Sale - Save 5% $ 80.99

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$ 76.94 USD
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$ 80.99

This product was last offered at the strikethrough price on
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$ 76.94 USD
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Includes bleeder screw
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 ...
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T#:340541
Part#: 17111742231
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Sale - Save 5% $ 17.99

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$ 17.09 USD
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$ 17.99

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$ 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
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T#:46616026
Part#: EPK0025
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Sale - Save 6% $ 74.99

This product was last offered at the strikethrough price on
06-29-2026

$ 70.63 USD
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$ 74.99

This product was last offered at the strikethrough price on
06-29-2026

$ 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
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T#:46616014
Part#: EPK0012
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Sale - Save 8% $ 29.99

This product was last offered at the strikethrough price on
06-29-2026

$ 27.65 USD
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Sale - Save 8%
$ 29.99

This product was last offered at the strikethrough price on
06-29-2026

$ 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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