Rein BMW Cooling System Parts & Accessories for BMW X Series F39 (2018+)

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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 Rein Aluminum Coolant Flange Connector - BMW & MINI B36 B46/B...
For vehicles with the earlier Gen1 B46/B48 engine - Not compatible with the later TU en...
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T#:33679696
Part#: 11118511205
In Stock
$ 50.99 USD
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$ 50.99 USD
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Plastic coolant flanges become brittle over time, which can cause them to crack and fail. Prevent overheating and coolant loss with this OEM Rein upgraded aluminum coolant flange.
Upper Coolant Hose
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T#:38195380
Part#: 17127617363
In Stock
$ 73.99 USD
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OEM Rein Engine Coolant Hose - Turbo Charger - BMW F48 F39 B46/B48 ...
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T#:40985138
Part#: 17127617377
In Stock
$ 70.99

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

$ 59.99 USD
Limited Qty Sale
Free Shipping on orders $49 and up
$ 70.99

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

$ 59.99 USD
Limited Qty Sale
Free Shipping on orders $49 and up
This OEM Rein coolant hose connects the auxiliary pump to the heat exchanger hose. Replace your old, cracked coolant hose with this new hose from Rein to prevent coolant loss and overheating.

Hose From Radiator Bottom - Thermostat CHR0800
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T#:38195379
Part#: 17127617368
In Stock
$ 45.99 USD
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OEM Rein Turbocharger Coolant Supply Line - BMW Gen2 B46/B48 2.0L ...
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T#:34315143
Part#: 11538629971
Ships in 4 Business Days
$ 47.99

This product was last offered at the strikethrough price on
04-28-2026

$ 42.99 USD
Free Shipping on orders $49 and up
$ 42.99 USD
Free Shipping on orders $49 and up
Turbo coolant supply lines feed coolant to the turbocharger, ensuring temperatures are kept in check. If your coolant line is leaking, it is important to replace it as soon as possible to prevent coolant loss, overheating, and turbo damage.
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OEM Rein Turbocharger Coolant Return Line - BMW & MINI B36 B46/B4...
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T#:45757431
Part#: 11539488188
Ships in 4 Business Days
$ 55.99 USD
Free Shipping on orders $49 and up
$ 55.99 USD
Free Shipping on orders $49 and up
The coolant return hose is responsible for taking cooling from the turbocharger and returning it back to the engine coolant system, allowing a free flow of coolant to keep the turbocharger temperatures under control.
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