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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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BMW E46 M54 AAF Low Temp Thermostat Kit - Partial

T#:7624632

Part#: 116211.2

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$ 85.00 USD

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BMW E46 M54 AAF Low Temp Thermostat Kit - Partial is an essential upgrade for enthusiasts looking to optimize engine performance and reliability. Developed by Advanced Auto Fabrication (AAF), this kit addresses the limitations of the factory M54 thermostat, which maintains a temperature range of 80-103°C and opens the mechanical failsafe at 110°C. For race conditions where maintaining a lower temperature is crucial, this kit replaces the stock electronic thermostat with a manual unit, allowing the engine to run at a safer and more efficient temperature. This upgrade not only enhances engine longevity but also reduces stress from high-temperature operation, minimizes heat soak, and increases power.

Optimal Temperature Control: Replaces the factory thermostat for improved engine temperature management.
Enhanced Engine Longevity: Operates at safer temperatures, reducing stress and extending engine life.
Increased Power: Lower operating temperatures can lead to better engine performance.
Reduced Heat Soak: Helps prevent overheating and ensures efficient cooling.
Improved Reliability: Manual thermostat unit offers more consistent performance in racing conditions.

Partial Kit Contents:

Thermostat housing plate
Thermostat
Installation hardware

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Bavarian Autosport Radiator Hose - Upper - E46 M52 M54

T#:640204

Part#: 17127510952

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05-03-2026

$ 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

T#:640203

Part#: 11531436408

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05-03-2026

$ 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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AAF Transmission Crossmembers 5-Speed - E46 Non-M

Fits ZF and Getrag Transmissions. Non-M models Only

T#:7608860

Part#: 116110

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$ 190.00 USD

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Since 2010, Advanced Auto Fabrication has been producing and developing both parts and full fledged race cars. Their knowledge base covers a wide range of vehicles both domestic and imported. In the specific case of BMW, the team at AAF has a particular affinity for building and designing components for BMW race cars. Ideal for the SE46 racing series, the AAF E46 5-speed Transmission Crossmember is a heavy-duty and worthwhile upgrade. The OEM thin cast aluminum cross member has been known to fail in multiple different ways. When using stiff engine and transmission mounts, the cross member can crack out and break around these mounting points. The cross member can also break from the high amounts of load transferred through the drive train. While chassis flex from hard cornering is being applied through the engine and transmission from the front cross member, this load is sent from the transmission back into the chassis at the transmission cross member. This is simply too much stress for the OEM cross member to hold up to under the extreme punishment of road racing. The AAF E46 Transmission Cross Member is completely constructed of 1/4' thick heavy-duty aluminum plate. It is designed specifically to cope with hours of endurance racing.

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Thermostat With Housing

T#:26494584

Part#: 11537509227

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05-03-2026

$ 49.99 USD

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AAF Low Temp Thermostat Kit - Full Kit - E46

T#:7624630

Part#: 116211

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$ 175.00 USD

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$ 175.00 USD

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Since 2010, Advanced Auto Fabrication has been producing and developing both parts and full fledged race cars. Their knowledge base covers a wide range of vehicles both domestic and imported. In the specific case of BMW, the team at AAF has a particular affinity for building and designing components for BMW race cars. The factory M54 thermostat is electronically controlled to keep the engine running between 80-103°C, whereas race cars like to maintain 80°C or less for maximum power. Additionally, the mechanical failsafe doesn’t open up until the coolant temperature reaches 110°C, or 230°F, which is about the point when most race cars are turned off and parked which is no good for the motor! The AAF E46 M54 Low Temp Thermostat Kit is designed to give the control of proper engine operating temperature back by replacing the stock electronic thermostat with a manual unit. This allows the engine to run at the proper, and much safer, operating temperature, improving engine longevity, reduces stress from high-temp. operation, reduces heat soak, and increases power! Full Kit Contents: Thermostat housing Thermostat housing plate Thermostat install hardware sealant

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BMW E46 AAF Aluminum Radiator Mounting Kit

T#:7608839

Part#: 11641

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$ 189.00 USD

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BMW E46 AAF Aluminum Radiator Mounting Kit provides a robust solution for mounting an aluminum radiator into the BMW E46 chassis without relying on the stock plastic mounts. Developed by Advanced Auto Fabrication, a company renowned for their expertise in producing high-performance race car components, this kit reflects their extensive knowledge and dedication to BMW race car design.

The mounting kit is designed to replace the stock mounting system and is compatible with lightweight aftermarket fans, as the stock electric fan cannot be used. Please note that this kit does not fit M3 models.

Durable Construction: Made from high-quality aluminum for strength and longevity.
Enhanced Cooling Efficiency: Allows for the use of aftermarket fans for improved cooling performance.
Race-Ready Design: Reflects Advanced Auto Fabrication's expertise in BMW race car components.
No Stock Plastic Mounts: Provides a more reliable and robust mounting solution than the factory system.

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OEM Nissens Radiator - Automatic - E46, Z4

For vehicles with automatic transmission only

T#:362222

Part#: 17119071519

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$ 173.39

This product was last offered at the strikethrough price on
06-02-2026

$ 165.05 USD

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The cooling system is a weak point on any E46. Many cars develop issues in as few as 50,000 miles.

Overheating an inline 6 engine almost always results in large repair bill, and sometimes a warped cylinder head.

Replace yours with a high-quality OEM Nissens radiator to prevent further issues and potential overheating.

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Expansion Tank Hose

T#:27572101

Part#: 64218376153

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05-03-2026

$ 38.34 USD

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Radiator Hose - Lower

T#:38655188

Part#: 11537830715

In Stock

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$ 22.53 USD

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Radiator Hose - Upper

T#:38621426

Part#: 11537830716

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$ 20.39 USD

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Active Autowerke Sport Fan Clutch - E36 E46

T#:397219

Part#: 14-010

Ships in 4 Business Days

5% off MSRP $ 259.00

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 246.99 USD

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5% off MSRP

$ 259.00

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 246.99 USD

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When you push your powerplant, thermodynamics push right back. The toll of high performance is higher heat load – and many stock components begin to complain. But Active Autowerke has you covered - this upgraded fan clutch increases viscous coupling of cooling fan blade speed to water pump speed, yielding increased airflow through the radiator for more efficient cooling. A simple, yet wonderful, thing.

This product fits the following BMWs:
1992-1999 E36 323i 325i 328i 330i M3
1998-2006 E46 323i 325i 328i 330i M3

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AAF E46 Transmission Crossmembers - 6-Speed Non-M

For use with solid front engine mounts only!

T#:7624639

Part#: 116222

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$ 190.00 USD

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Since 2010, Advanced Auto Fabrication has been producing and developing both parts and full fledged race cars. Their knowledge base covers a wide range of vehicles both domestic and imported. In the specific case of BMW, the team at AAF has a particular affinity for building and designing components for BMW race cars. Ideal for the SE46 racing series, the AAF E46 6-speed Transmission Crossmember is a heavy-duty and worthwhile upgrade. The OEM thin cast aluminum cross member has been known to fail in multiple different ways. When using stiff engine and transmission mounts, the cross member can crack out and break around these mounting points. The cross member can also break from the high amounts of load transferred through the drive train. While chassis flex from hard cornering is being applied through the engine and transmission from the front cross member, this load is sent from the transmission back into the chassis at the transmission cross member. This is simply too much stress for the OEM cross member to hold up to under the extreme punishment of road racing. The AAF E46 Transmission Cross Member is completely constructed of 1/4' thick heavy-duty aluminum plate. It is designed specifically to cope with hours of endurance racing.

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E46 Upper Radiator Hose - 11531436406

T#:36981064

Part#: 11531436406

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$ 31.99

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05-03-2026

$ 24.99 USD

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Over time, prolonged exposure to high-temperature coolant can take a toll on your vehicle's hoses. Made from reinforced rubber, these hoses are prone to wear and failure in various ways, including splitting at hose clamps, swelling, cracking, or breaking. Any of these issues can lead to coolant loss and potentially leave you stranded. Replacing your hoses at the first sign of wear is essential to maintaining a properly functioning cooling system.

This replacement hose is designed with the correct diameter, bends, and length for a precise fit, making it an ideal solution for swelled or damaged hoses. With straightforward installation, this hose provides peace of mind, whether you're embarking on a long road trip or simply commuting to work.

When replacing your radiator hose, some coolant loss is unavoidable. Browse our website to find the exact replacement coolant and other parts for your vehicle, delivered straight to your door. Don’t forget to order a new thermostat housing as well—factory plastic units often crack or warp during removal, and replacing them ensures a complete and reliable repair.

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Water Pipe - M54 E46 E58 E83

T#:36981061

Part#: 11537502000

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Sale - Save 17% $ 35.99

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05-03-2026

$ 29.74 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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AAF E46 Transmission Crossmembers - 6-Speed M

For M Models

T#:7624640

Part#: 116223

Ships in 4 Business Days

$ 190.00 USD

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Since 2010, Advanced Auto Fabrication has been producing and developing both parts and full fledged race cars. Their knowledge base covers a wide range of vehicles both domestic and imported. In the specific case of BMW, the team at AAF has a particular affinity for building and designing components for BMW race cars. Ideal for the SE46 racing series, the AAF E46 6-speed Transmission Crossmember is a heavy-duty and worthwhile upgrade. The OEM thin cast aluminum cross member has been known to fail in multiple different ways. When using stiff engine and transmission mounts, the cross member can crack out and break around these mounting points. The cross member can also break from the high amounts of load transferred through the drive train. While chassis flex from hard cornering is being applied through the engine and transmission from the front cross member, this load is sent from the transmission back into the chassis at the transmission cross member. This is simply too much stress for the OEM cross member to hold up to under the extreme punishment of road racing. The AAF E46 Transmission Cross Member is completely constructed of 1/4' thick heavy-duty aluminum plate. It is designed specifically to cope with hours of endurance racing.

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Motorsport Thermostat - 60C - Complete with Housing - M54 / M52tu ...

T#:1171

Part#: TMS1171

Ships in 9 Business Days

$ 415.45 USD

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This is a genuine BMW Motorsport part, designed specifically for BMW racing applications. We use this exact thermostat setup in our Championship-winning E46 330i race car. It is designed to be used on all M54 and M52TU double-VAN0S engines, as used in the 1999-2000 E46 323/328 and 2001-2005 E46 325/330. This 60 degree C (140 defrees F) thermostat comes complete with plastic thermostat housing. It does not use the plug and wiring for the stock DME so this should only be used with an aftermarket engine management system (Motec, Bosch, etc).

When doing any sort of repair or maintenance there is no replacement for genuine factory parts. Turner Motorsport carries the Genuine BMW brand with pride and has the parts you need to complete your next project with confidence.

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Automatic Transmission Thermostat

T#:15511829

Part#: 17 111437362

Ships on Aug 14, 2026

Sale - Save 3% $ 37.99

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05-03-2026

$ 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

T#:36981065

Part#: 11517838159

Ships on Dec 2, 2026

Sale - Save 20% $ 138.99

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

$ 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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Sachs Radiator Fan Clutch - E34, E36, E39, E46, E53, Z3

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:591739

Part#: 11527505302

Back Ordered

$ 133.99

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

$ 129.99 USD

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Common source of engine overheating

Motorsport Thermostat - 55 (NO LONGER AVAILABLE)

T#:337991

Part#: 11531417215

Back Ordered

Starting at $ 232.98 USD

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Starting at $ 232.98 USD

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E46M3 Motorsport Thermostat 55C (Also fits Euro E36 M3 engine) A Genuine BMW part this thermostat opens at a much lower temperature than stock to keep your S54 engine (or Euro S50/S52 engine) running cooler in race applications.

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

T#:640140

Part#: 17111712788

In Stock

Sale - Save 39% $ 3.99

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05-03-2026

$ 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.

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

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

Heater Hose

T#:38621424

Part#: 64218363198

Ships on Aug 19, 2026

Sale - Save 21% $ 10.99

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05-03-2026

$ 8.66 USD

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

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

T#:38621423

Part#: 64218376999

Ships in 2 Business Days

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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This product was last offered at the strikethrough price on
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