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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BMW - Engine/Cooling
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Meyle - Corporate Logo
T#:40444296
Part#: 11531705224
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$ 35.99 USD
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$ 35.99 USD
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Over the years and with exposure to extremely hot coolant, the coolant hoses in your vehicle can take a beating. Being made of reinforced rubber, these hoses can fail in a number of ways. Splitting at a hose clamp, swelling, cracking, and breaking are just a few of the ways this hose can leave you stranded. Replace it at the first sign of wear to keep your coolant in your engine. With the proper diameter, bends, and lengths, this is the perfect replacement for any swelled or damaged hose. An easy installation, it's piece of mind the next time you are on a long trip or your morning commute.
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Coolant Level Sensor
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Meyle - Corporate Logo
T#:594511
Part#: 61318360876
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$ 27.99 USD
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Monitors the coolant level in the expansion tank. This sensor is critical in keeping tabs of your cooling systems health.
Auxillary Fan Switch
For vehicles with production date from 09/1998
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Meyle - Corporate Logo
T#:4934936
Part#: 3148210000
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$ 18.99 USD
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$ 18.99 USD
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The auxiliary fan switch activates the auxiliary cooling fan to provide additional cooling under high heat loads, and when the car is stationary. Also known as the coolant temperature sending unit, comes with related o-ring
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Coolant Temperature Sensor
Located on water pump housing For vehicles with production date from 09/1998
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Meyle - Corporate Logo
T#:594615
Part#: 13621703993
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$ 18.99 USD
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$ 18.99 USD
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This is the coolant temperature sensor used in many BMW models from the mid-1990s to the mid-2000s. The engine computer relies on the coolant temp to set the fuel mapping for the engine. As the car warms up the computer changes the fuel mixture. If your car is running a bit rich (too much fuel) it could be because this sensor is failing and not sending the correct info to the computer.

This sensor is located in a variety of places depending on the engine. But it's one of those easy replacement items 'while you're in there' when doing a water pump or thermostat replacement.

This coolant temp sensor fits the following BMWs:
1996-1999 E36 BMW 323is 323ic 328i 328is 328ic M3, located in cylinder head
1999-2003 E39 BMW 540i, located on side of water pump
1999-2001 E38 BMW 740i 740il, located on side of water pump
1995-1996 E38 BMW 750il, located on side of water pump
1990-1999 E31 BMW 850i 850ci, located on side of water pump
2000-2006 E53 BMW X5 3.0i, located in cylinder head
2000-2006 E53 BMW X5 4.4i/4.6is/4.8is, located on side of water pump
1997-2002 Z3 BMW Z3 2.5i Z3 3.0i, located in cylinder head
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Fluid Level Sensor
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Meyle - Corporate Logo
T#:5973204
Part#: 17117546548
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$ 13.99 USD
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MEYLE-ORIGINAL: True to OE fluid level sensor. Used in multiple locations. 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. Comparable OE Cross Reference - 17117546548
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Rein Coolant Hose - E39
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Rein - Corporate Logo
T#:379777
Part#: 64218391003
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$ 31.99 USD
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$ 31.99 USD
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Hose that runs from the engine block to the water valve. Over time, coolant hoses begin to get brittle and are susceptible to cracking and splitting. Replace your cracked or leaking coolant hose to prevent further leaks and potentially catastrophic failure.
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URO Air Temperature Sensor - BMW X5 M5 525i 528i 530i 540i
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URO - Corporate Logo
T#:592644
Part#: 64118391392
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$ 7.99 USD
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URO Parts is one of the leading manufacturers of high quality direct replacement aftermarket components, covering a wide range of makes and models. All of their replacement parts are manufactured to ISO 9000 certification standards, so you can expect long lasting performance from URO Parts.
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Auxiliary Fan Switch
For vehicles with production date from 09/1998
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URO - Corporate Logo
T#:376847
Part#: 13621433077
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$ 10.99 USD
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$ 10.99 USD
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Comes with related o-ring

O-Ring - Coolant Pipe - BMW
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Elring - Corporate Logo
T#:14949060
Part#: 11411304178
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$ 3.99

This product was last offered at the strikethrough price on
05-07-2026

$ 2.99 USD
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$ 2.99 USD
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Over time, o-rings will wear and eventually fail, leading to leaks and other issues. Avoid this by replacing them with new examples!

BMW Coolant Expansion Tank With Cap
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Rein - Corporate Logo
T#:46616009
Part#: EPK0013
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$ 64.99 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. This replacement will fit perfectly and provide the same heating and cooling characteristics as an original unit. When replacing, be sure to have some extra coolant. Check ECS Tuning's website for a wide variety of coolants specifically designed for your car. Most German vehicles require specialized coolant. Be sure to pick up the proper coolant when refilling to avoid damage or premature corrosion.
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Bremmen Parts Thermostat Assembly - E38, E39
For vehicles with production date up to 09/1998
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Bremmen Parts - Corporate Logo
T#:388457
Part#: 11531437526
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This product was last offered at the strikethrough price on
05-03-2026

$ 48.44 USD
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$ 56.99

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

$ 48.44 USD
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Comes with aluminum housing, o-ring & sensor
Gates Coolant Hose - E39
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Gates - Corporate Logo
T#:596352
Part#: 64218387521
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$ 64.99 USD
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From heater core to engine