Rein BMW Cooling System Parts & Accessories for BMW 5 Series E39 (1996-2003)

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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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Rein - Corporate Logo
T#:6945
Part#: 11531711384
In Stock at Vendor
$ 68.99 USD
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$ 68.99 USD
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This is the cooling system return hose that goes from the automatic transmission cooling thermostat to the hose that comes off the lower water pump outlet.1999-2003 E39 BMW 540i
1999-2001 E38 BMW 740i 740il
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Coolant Expansion Tank
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:591959
Part#: 17111741167
Ships in 1 Business Day
$ 69.99 USD
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$ 69.99 USD
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Plastic has a limited lifespan - replace every 80,000 miles
BMW E39 Coolant Expansion Tank
For vehicles with production date from 09/1998
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:388645
Part#: 17111436381
Back Ordered
$ 87.99 USD
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$ 87.99 USD
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BMW E39 Coolant Expansion Tank is an essential component designed to maintain the proper coolant level in your vehicle's cooling system. Manufactured with high-quality materials, this expansion tank ensures reliable performance and durability, preventing engine overheating by accommodating the expansion of coolant as it heats up. The kit includes a level sensor and cap, providing everything needed for a seamless installation. This expansion tank is specifically engineered to meet the exact specifications of your BMW E39, offering a perfect fit and optimal functionality.

  • Complete Kit: Includes level sensor and cap for easy installation.
  • High-Quality Construction: Built with durable materials for long-lasting performance.
  • Prevents Overheating: Helps manage coolant expansion, ensuring engine protection.
  • Exact Fit: Designed to meet the precise specifications of your BMW E39.
  • Enhanced Reliability: Ensures proper coolant level maintenance for optimal cooling system function.
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Thermostat With Housing
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:582356
Part#: 11537509227
Ships in 1 Business Day
$ 89.99 USD
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$ 89.99 USD
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Stop leaks before they start with this new Thermostat With Housing from Rein.