BMW Cooling System Parts & Accessories for BMW 3 Series E46 (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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Coolant Hose With Quick Connectors
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Febi - Corporate Logo
T#:17339415
Part#: 11531436410
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$ 28.99 USD
$ 28.99 USD
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.
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Bav Auto Temperature Sensor - BMW E39 E46 E9X E60 F01/02
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Bavarian Autosport - Corporate Logo
T#:639833
Part#: 13621433076
In Stock
Sale - Save 20% $ 14.99

This product was last offered at the strikethrough price on
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$ 11.99 USD
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Sale - Save 20%
$ 14.99

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

$ 11.99 USD
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This is the coolant temperature sensor used in many BMW models from the late-1990s to the mid-2010s. 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. 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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Heater Hose
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Bremmen Parts - Corporate Logo
T#:38621423
Part#: 64218376999
Ships in 8 Business Days
Sale - Save 22% $ 20.99

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

$ 16.31 USD
Free Shipping on orders $49 and up
Sale - Save 22%
$ 20.99

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

$ 16.31 USD
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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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Meyle - Coolant Hose - Lower Right E46
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Meyle - Corporate Logo
T#:40478120
Part#: 11531436408
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$ 32.99 USD
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Upgrade your BMW’s cooling system with a dependable solution that meets or exceeds OEM quality.
Auxillary Fan Switch
Mounted in upper radiator hose, controls operation of auxiliary fan Mounted in lower radiator hose, controls operation of auxiliary fan
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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 Flange - Rear/Engine Block
Fits European models only
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Meyle - Corporate Logo
T#:55533481
Part#: 11531708808
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New Item
$ 9.99 USD
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$ 9.99 USD
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This Meyle Original-grade replacement coolant flange is the perfect solution for refreshing your BMW’s cooling plumbing back to factory-fresh operation.
URO Radiator Mounting Bracket - E46 Z4
Right Lower Left Lower
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URO - Corporate Logo
T#:593030
Part#: 17111436264
Back Ordered
$ 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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Auxiliary Fan Switch
Mounted in upper radiator hose, controls operation of auxiliary fan Mounted in lower radiator hose, controls operation of auxiliary fan
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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

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
Radiator Drain Plug With Housing
For vehicles with automatic transmission only
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URO - Corporate Logo
T#:593032
Part#: 17111437360
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$ 10.99 USD
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$ 10.99 USD
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This is the drain plug (adjustment screw) for automatic transmission equipped cars.
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
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$ 8.99 USD
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Mounts to top of radiator bracket, 2 per vehicle.
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