BMW Cooling System Parts & Accessories for BMW E46 M3 S54 (1999-2005)

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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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Auxiliary Fan Switch
Mounted in upper radiator hose, controls operation of auxiliary fan
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URO - Corporate Logo
T#:376847
Part#: 13621433077
Back Ordered
$ 10.99 USD
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$ 10.99 USD
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Comes with related o-ring
Meistersatz Temperature Sensor
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Meistersatz - Corporate Logo
T#:379740
Part#: 13621433076
Ships in 3 Business Days
$ 15.99 USD
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Monitors coolant / oil temperature
Lower Radiator Mount - Priced Each
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MTC - Corporate Logo
T#:361005
Part#: 17111178412
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$ 2.03 USD
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This is the small lower rubber mount that goes on the bottom of the radiator. These mounts sit down into mount 17111723337. Fits left or right side - priced each

URO Radiator Mounting Bracket - E46 Z4
Right Lower
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URO - Corporate Logo
T#:593030
Part#: 17111436264
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$ 9.99 USD
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$ 9.99 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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DO88 Coolant Hoses - Blue - E46 M3
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DO88 - Corporate Logo
T#:13924830
Part#: DO88KIT70B
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$ 256.99 USD
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Made out of high-quality silicone, these hoses display the highest levels of durability and quality. With three to five layers of armory the hoses are designed to withstand high pressure and heat for an extended period of time. The OE hoses are known to crack and leak but this hose kit eliminates any chance of that.
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BMW Radiator Hose Kit - 11537830715
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Rein - Corporate Logo
T#:46719180
Part#: CHK0376R
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$ 43.99 USD
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Keep your cooling system sealed, strong, and ready for anything with this Rein radiator hose kit—your all-in-one fix for cracked, leaking, or worn factory hoses. Years of heat, pressure, and age can cause rubber to weaken, split, or swell, setting the stage for coolant leaks and potential overheating. Rein hoses are engineered to meet or exceed OEM standards, built from premium, heat-resistant materials that can take on extreme temperatures and system pressures without faltering. Each hose features factory-correct bends, fittings, and diameters for an exact, hassle-free installation—no cutting or forcing required. Whether you’re tackling a full cooling system refresh or chasing down a small coolant leak, this Rein kit provides everything needed to restore confidence and performance under the hood. Why choose this Rein radiator hose kit: Factory-level precision – Direct-fit replacements that deliver OEM-quality reliability. Built to last – Resists cracking, swelling, and chemical damage from daily heat cycling. Confidence restored – Prevents coolant loss, overheating, and on-road breakdowns. All-in-one upgrade – Includes upper and lower hoses for a complete system refresh. If keeping your BMW’s cooling system running tight and trouble-free is the goal, Rein brings the dependable quality and fitment you can count on—engineered to perform just like factory, mile after mile.
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Radiator Support Bracket
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Rein - Corporate Logo
T#:14122755
Part#: 17117514402
Special Order: No Guaranteed ETA
$ 8.99 USD
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Mounts to top of radiator bracket, 2 per vehicle.