BMW Cooling System Parts & Accessories for BMW 3 Series E30 (1984-1991)

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The cooling system is arguably the weakest point in numerous BMWs. If you drive an aging BMW or plan on taking your car to the track like we do, we recommend beefing up your cooling system before going to the track. Generally, the main components in your cooling system that are prone to failure include the following: expansion tank, factory hoses, water pump, thermostat, fan (especially if your vehicle comes factory with a clutch fan), and radiator. Factory BMW expansion tanks are plastic and prone to either breaking off at connection points or combusting. As factory rubber hoses age they either crack or break over time - we offer silicone cooling hose upgrades for most applications to avoid future failures. If you have an older vehicle, your water pump likely comes from the factory with a plastic impeller - we offer upgraded water pumps with metal impellers that are far more reliable. Newer model BMWs utilize electric water pumps - BMW spent millions of dollars engineering these water pumps, but they fail so often that we recommend replacing at 60,000 mile service intervals to avoid being stranded on the side of the road. In terms of thermostats, we offer various upgraded thermostats for racing applications. If your BMW utilizes a clutch fan from the factory, we have several options available in terms of universal electric fans - we recommend replacing these to avoid sending brittle plastic fan blades through your hood. For radiators, we recommend swapping out your radiator for one that does not use plastic connection points like your factory radiator.

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OEM Style Hose Clamps
OEM Style Hose Clamps
Turner Motorsport - Corporate Logo
T#:338927
Part#: HOSE-CLAMPS
In Stock
Sale - Save 3% $ 3.99

This product was last offered at the strikethrough price on
06-13-2026

Starting at $ 3.87 USD
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Sale - Save 3%
$ 3.99

This product was last offered at the strikethrough price on
06-13-2026

Starting at $ 3.87 USD
Free Shipping on orders $49 and up
Add to Wish List
Hose clamps for radiator hoses, coolant hoses, vacuum hoses, or intake hoses. These hose clamps are the same style as your OEM hoses with a smooth inside band to prevent cutting into the hose material.
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Moroso Aluminum Coolant Expansion Tank - E30 M3
Moroso Aluminum Coolant Expansion Tank - E30 M3
Moroso - Corporate Logo
T#:29666103
Part#: 63799
In Stock at Vendor
$ 459.99 USD
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$ 459.99 USD
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The coolant expansion tank provides hot coolant with a place to travel, preventing pressure buildup within your cooling system. On many BMWs, this component is constructed from plastic. While cheap to replace and manufacture, a failed cooling tank can cause costly engine damage.

With this issue in mind, Moroso designed a high-quality replacement. Featuring TIG welded, 100% aluminum construction, this tank is sure to outperform it's factory counterpart.

Features:

Bolt-in replacement for stock cracked or discolored tanks Fabricated aluminum Features billet aluminum filler neck and integrated sight glass to monitor coolant level Can be polished, painted, powder coated or left as-is Moroso radiator cap (63320) included

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Thermostat - 80°C
Thermostat - 80°C
Mahle - Corporate Logo
T#:594727
Part#: 11531713040
Ships on Aug 4, 2026
$ 35.99 USD
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$ 35.99 USD
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The thermostat on your vehicle controls the flow of coolant based on temperature. When you just start your engine, the thermostat remains closed to accelerate the warm up process. After a few minutes, it opens up to allow the warm fluid to flow. If your vehicle is overheating but not blowing warm air from the heater, the problem is more than likely your thermostat.
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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 ...
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
Free Shipping on orders $49 and up
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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
Free Shipping on orders $49 and up
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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