BMW Coolant Expansion Tanks for BMW 3 Series E30 (1984-1991)

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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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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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Rein - Corporate Logo
T#:340541
Part#: 17111742231
In Stock
$ 17.99 USD
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$ 17.99 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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Coolant Level Sensor
Coolant Level Sensor
Bremmen Parts - Corporate Logo
T#:30728984
Part#: 61311378320
In Stock
Sale - Save 56% $ 34.99

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

$ 15.29 USD
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Sale - Save 56%
$ 34.99

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

$ 15.29 USD
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Bremmen Coolant Bleeder Screw - BMW E30 E36 E38 E39 E46 E83 E90 Z4
Bremmen Coolant Bleeder Screw - BMW E30 E36 E38 E39 E46 E83 E90 Z4 ...
Bremmen Parts - Corporate Logo
T#:640140
Part#: 17111712788
In Stock
Sale - Save 39% $ 3.99

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

$ 2.44 USD
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Sale - Save 39%
$ 3.99

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

$ 2.44 USD
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Plastic bleeder screw for cooling system is used to bleed air that would otherwise create an air pocket and lead to overheating. Includes o-ring seal.
Meyle Expansion Tank Cap
Meyle Expansion Tank Cap
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Meyle - Corporate Logo
T#:579357
Part#: 3148009004
In Stock
Sale - Save 40% $ 14.99

This product was last offered at the strikethrough price on
05-15-2026

$ 8.99 USD
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Sale - Save 40%
$ 14.99

This product was last offered at the strikethrough price on
05-15-2026

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Replace worn or missing pieces.
Rein Expansion Tank Cap - E30, E34
Rein Expansion Tank Cap - E30, E34
For vehicles with production date from 09/1987
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Rein - Corporate Logo
T#:592018
Part#: 17137639023
Ships in 3 Business Days
$ 14.99 USD
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$ 14.99 USD
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1.4 Bar pressure
Expansion Tank Cap
Expansion Tank Cap
For vehicles with production date from 09/1987
MTC - Corporate Logo
T#:371228
Part#: 17111742232
Ships in 9 Business Days
$ 6.99 USD
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$ 6.99 USD
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1.4 Bar pressure. Older radiator caps being to lose their ability to hold pressure over time. Resulting in a lower boiling point for the coolant system.
Meyle Expansion Tank Cap
Meyle Expansion Tank Cap
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Meyle - Corporate Logo
T#:5958735
Part#: 17111742232
Special Order: No Guaranteed ETA
$ 10.99 USD
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$ 10.99 USD
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Wulf Gaertner Autoparts AG manufactures and markets automotive spare parts under its MEYLE brand. Since its foundation in 1958, Wulf Gaertner Autoparts has been an owner-operated, unlisted family business on the aftermarket scene. Since 1995, Wulf Gaertner Autoparts AG has been manufacturing and trading under its MEYLE brand. They pride themselves on top-grade quality-tested spare parts for passenger cars, vans and commercial vehicles. The coolant expansion tank cap keeps necessary pressure on your coolant to increase efficiency. If you have an overheating issue in your vehicle, a simple, quick, and inexpensive part to replace is this cap. Often times, the coolant is not kept under enough pressure to keep it from boiling or expanding too much. This cap keeps all the heat and liquid inside the coolant system for maximum efficiency. Should be replaced each time major coolant system service is performed.
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Coolant Expansion Tank With Cap - 17111712835
Coolant Expansion Tank With Cap - 17111712835
Rein - Corporate Logo
T#:46616014
Part#: EPK0012
Back Ordered
$ 29.99 USD
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$ 29.99 USD
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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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