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Bremmen Parts 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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Bavarian Autosport Radiator Hose - Upper - E46 M52 M54

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T#:640204

Part#: 17127510952

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$ 27.74 USD

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Replacement Upper Radiator Hose for E46 3 series (Non-M3). We recommend replacing the Coolant Temperature Sensor while replacing this hose as the original sensor is often damaged while trying to remove it from the old hose. 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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Bav Auto Radiator Hose - Lower - E46 M52 M54

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T#:640203

Part#: 11531436408

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$ 31.20 USD

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OEM Replacement Lower Radiator Hose for E46 3 series (Non-M3). We recommend replacing the Coolant Temperature Sensor while replacing this hose as the original sensor is often damaged while trying to remove it from the old hose. 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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Expansion Tank Hose

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T#:27572101

Part#: 64218376153

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$ 38.34 USD

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Thermostat With Housing

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T#:26494584

Part#: 11537509227

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$ 45.99 USD

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Radiator Hose - Lower

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T#:38655188

Part#: 11537830715

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$ 22.53 USD

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Radiator Hose - Upper

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T#:38621426

Part#: 11537830716

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$ 20.39 USD

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Auxiliary Cooling Fan Assembly - 17117561757

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T#:36913373

Part#: 17117561757

Ships on Oct 13, 2026

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$ 169.99 USD

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The auxiliary fan in your vehicle serves an extremely important role. When your car reaches temperatures that may be hazardous to your engine, the auxiliary fan moves air through the radiator to provide better cooling. Usually activated during times of stationary vehicle operation, it supplements the air usually driven through the radiator by driving down the road.

If your vehicle is getting too hot during traffic or at stop lights, your auxiliary fans are probably faulty. Replace yours with this piece from Bremmen Parts to restore the factory cooling in your vehicle and prevent catastrophic damage to your engine. Even if your fans are still operational but the blades are damaged or cracked, replacement is the only solution.

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Water Pipe - M54 E46 E58 E83

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T#:36981061

Part#: 11537502000

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$ 31.44 USD

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Water pipes play a crucial role in maintaining proper engine cooling. If cracked, they must be replaced immediately to prevent engine overheating. This water pipe runs from the rear of the water pump housing to the expansion tank hose. It comes complete with all necessary seals for a hassle-free installation.

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Automatic Transmission Thermostat

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T#:15511829

Part#: 17 111437362

Ships on Oct 20, 2026

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$ 36.85 USD

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Heat exchanger for your automatic transmission, usually changed when you replace your expansion tank.

Bremmen Parts Water Pump - E46 M3 S54

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T#:36981065

Part#: 11517838159

Ships on Dec 2, 2026

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$ 110.97 USD

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A failing water pump is a recipe for engine overheating and costly internal damage. Keep your coolant flowing and your engine protected by replacing your aging pump with this high-quality OE unit from Bremmen Parts.

Water pump replacement is suggested at 60,000 - 80,000 miles.

This pump includes the alignment dowel, sealing gasket, and thermostat sealing o-ring. We recommend picking up a water pipe sealing o-ring (11537830712) and thermostat (11531318274) for a comprehensive service.

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Bremmen Coolant Bleeder Screw - BMW E30 E36 E38 E39 E46 E83 E90 Z4 ...

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T#:640140

Part#: 17111712788

Ships on Dec 23, 2026

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09-02-2026

$ 2.44 USD

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Plastic bleeder screw for cooling system is used to bleed air that would otherwise create an air pocket and lead to overheating. Includes o-ring seal.

Heater Hose

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T#:38621424

Part#: 64218363198

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$ 8.66 USD

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Bremmen Auxiliary Fan Temperature Switch - E46 E39 E9X E60 E70 E53 ...

Mounted in upper radiator hose, controls operation of auxiliary fan Mounted in lower radiator hose, controls operation of auxiliary fan

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T#:640141

Part#: 13621433077

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$ 16.79 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

Bremmen Engine Fan Blade - 11 Blades, 420mm - BMW M30 S38 M50 M52 S5...

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T#:640149

Part#: 11521712058

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$ 18.76 USD

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This fan is driven by the serpentine belt, engaged by the fan clutch. If you have bad motor mounts, it's quite common for the blades of this fan to make contact with the radiator or radiator shroud, essentially self-destructing the fan into many pieces. Be sure to get a new fan clutch, while you are replacing this.

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Heater Hose

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T#:38621423

Part#: 64218376999

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$ 16.31 USD

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