BMW Coolant Expansion Tanks for BMW Z Series E85/6 (2003-2008)

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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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Expansion Tank Replacement Kit
Expansion Tank Replacement Kit
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Packaged by Turner - Corporate Logo
T#:15744017
Part#: N524ECSTNKKT-KT
In Stock
Sale - Save 40% $ 166.99

This product was last offered at the strikethrough price on
04-03-2026

$ 100.95 USD
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Sale - Save 40%
$ 166.99

This product was last offered at the strikethrough price on
04-03-2026

$ 100.95 USD
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The coolant expansion tank in your vehicle gives additional fluid a place to go after expansion and contraction from temperature change. Because it is subjected to such drastic changes on a regular basis, it can often crack or break. You want to keep all the coolant in your vehicle in the cooling system. If your tank has experienced damage such as cracking, nipples breaking off, or mounting point damage, you will need to replace it. The kit includes: Expansion tank with level sensor URO expansion tank cap Genuine BMW expansion tank grommet Genuine BMW mounting bolts
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Rein Expansion Tank Mounting Plate - E46, Z4
Rein Expansion Tank Mounting Plate - E46, Z4
For vehicles with automatic transmission only
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:402139
Part#: 17111436251
Ships in 2 Business Days
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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Mounts to the side of the radiator for retaining the expansion tank
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 2 Business Days
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
Free Shipping on orders $49 and up
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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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