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BMW Cooling System Parts & Accessories

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

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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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AAF Transmission Crossmembers 5-Speed - E46 Non-M

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Fits ZF and Getrag Transmissions. Non-M models Only

T#:7608860

Part#: 116110

In Stock at Vendor

$ 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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BMW E46 AAF Aluminum Radiator Mounting Kit

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:7608839

Part#: 11641

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$ 189.00 USD

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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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AAF Low Temp Thermostat Kit - Full Kit - E46

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:7624630

Part#: 116211

In Stock at Vendor

$ 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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Aluminum Thermostat Housing Kit - M50

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:397222

Part#: 14-009

In Stock

$ 56.99

This product was last offered at the strikethrough price on
06-18-2026

$ 52.99 USD

Limited Qty Sale

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$ 56.99

This product was last offered at the strikethrough price on
06-18-2026

$ 52.99 USD

Limited Qty Sale

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Plastic thermostat housing cracked on your M50?

Here are your choices: you can wait for the plastic factory thermostat housing cover to break and cause major overheating. (Even with a new stock cover, it won’t take long.) Or you can install a thoughtfully engineered all-aluminum thermostat housing cover from Active Autowerke and never experience this type of failure again. Currently there is no factory upgraded part to this problem. This is an aluminum extruded part that has all of the openings machine properly to fit like factory; from the mounting bolt holes, the seating of the thermostat to the sealing opening for the ORANGE gasket. Forged to exact factory tolerances, everything fits and this unit is a true easy bolt-on – especially suited for racing or load conditions like heavy traffic, where engine temp can rise rapidly. The housing is guaranteed never to break from overheating or over-tightening, and its CNC machined surface ensures a precise seat.

Unit comes complete with a new ORANGE sealing gasket; a new thermostat is recommended but not included.
For hotter climates, a 71 degree thermostat is recommended over the 82 degree unit.

Anything and everything BMW is the mantra at Active Autowerke. Since 1981 they have been serving the BMW community with custom turbocharger kits to a myriad of other innovative and inspiring performance parts.

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Active Autowerke Sport Fan Clutch - E36 E46

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:397219

Part#: 14-010

Ships in 2 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

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
For use with solid front engine mounts only!

T#:7624639

Part#: 116222

In Stock

$ 190.00 USD

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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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AAF E46 Radiator Fan Shroud

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:7624641

Part#: 116251

Ships in 3 Business Days

$ 140.00 USD

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$ 140.00 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. AAF has created a light-weight fan shroud for your E46 race car. Equipped with 7 flaps to let as much air through as possible at speed and fits a 14' fan. Seamlessly attaches to the AAF Radiator Mounts. The shroud creates a vacuum to expand the fan’s ability to pull from the entire surface area of the radiator. This creates cooler temps under the hood with the benefit of 7 flaps that allow the most air to pass through. **AAF states fitment has only been thoroughly tested with their radiator mounts. No fitment info for the stock plastic mounts is available at this time. AAF has created a light-weight fan shroud for your E46 race car. Equipped with 7 flaps to let as much air through as possible at speed and fits a 14' fan. Seamlessly attaches to the AAF Radiator Mounts. The shroud creates a vacuum to expand the fan’s ability to pull from the entire surface area of the radiator. This creates cooler temps under the hood with the benefit of 7 flaps that allow the most air to pass through. **AAF states fitment has only been thoroughly tested with their radiator mounts. No fitment info for the stock plastic mounts is available at this time. *Does not include fan.

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AAF E46 Transmission Crossmembers - 6-Speed M

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
For M Models

T#:7624640

Part#: 116223

Ships in 3 Business Days

$ 190.00 USD

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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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Active Autowerke Thermostat Bypass/Delete Tube - S65

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:2302749

Part#: 14-016

Ships in 10 Business Days

$ 141.99 USD

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$ 141.99 USD

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CNC machined coolant/water thermostat bypass tube to improve flow on and off the track. Easy plug and play installation and a durable anodized coating make this a simple and reliable temperature control solution.

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Active Autowerke Cnc Aftercooler Cooling Kit - F8x S55

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T#:5886968

Part#: 15-012

Ships in 3 Business Days

$ 2,849.99 USD

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$ 2,849.99 USD

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BMW's S55 motor is a modern marvel but one weak point, which Active identified is the entire cooling system for the intake which comprises the charge pipe, the aftercooler and the heat exchanger (or radiator). Finally there is a S55 aftercooler kit upgrade that is good enough to carry the Active Autowerke brand. Years of success in developing cars for motorsport has allowed Active to leverage its expertise to the top-mount charge air cooler on the F80 M3, F82 M4 and F87 M2 Competition. This aftercooler was made for the S55 and crafted using only high-grade aluminum to outperform the factory aftercooler in all situations from everyday driving to the toughest racing. The factory cooler was built to support a specific power target and environment. Many of you have increased the performance of the S55 which quickly overwhelms the stock cooler leading to heat soak and higher intake air temperatures which triggers the ECU to downgrade the performance until cooler air returns. Active's focus was not on a mass-market aesthetic add-on but a properly engineered improvement over the existing hardware. Active uses a tube-and-fin core designed specifically for the S55 and included turbulators to maximize the cooling efficiency in as small a package as possible. The end tanks are billet machined aluminum, not cast, folded, or bonded and ensure even distribution of the water throughout the internal aftercooler cores. High precision fittings, CNC machining, and TIG welding throughout ensures the highest quality construction to prevent pressure loss, and the lowest weight, in a bolt-on replacement. But Active also didn’t leave the aesthetics by the wayside as we dip the visible top of the aftercooler in a carbon fiber coating giving your installed cooling system a decidedly top market look to match the improved cooling performance. The Active silicone charge pipes for the F80 M3, F82/F83 M4 and the F87 M2 Competition improve the flow over the stock, compressed plastic pipes. The Active Silicone Charge Pipes allow you to maximize power on your F8X by securing all the boost that your S55 is making. These pipes replace the hot-side pipes leaving the turbos and into the top-mount aftercooler. The stock S55 charge pipes are notorious for developing hairline fractures at their plastic seams. These fractures or cracks are unnoticeable to the naked eye, but under boost pressure they open up leaking the desired charged air into the engine bay, and consequently can rob your S55 of it's full power potential. In addition, these leaks can trigger your S55's turbochargers to work harder to hit and maintain target boost pressure, potentially wearing them out sooner. Active uses silicone in this area because it will not contribute to heat soak and it's easier to mold for the correct clearances. Active uses a 5-layer silicone hose with all needed adapters and stainless hose clamps included. It fits perfectly with our CNC’d top-mount cooler.

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BMW Cooling System Parts & Accessories

Sub-Categories

BMW E46 M54 AAF Low Temp Thermostat Kit - Partial

AAF Transmission Crossmembers 5-Speed - E46 Non-M

BMW E46 AAF Aluminum Radiator Mounting Kit

AAF Low Temp Thermostat Kit - Full Kit - E46

Aluminum Thermostat Housing Kit - M50

Active Autowerke Sport Fan Clutch - E36 E46

AAF E46 Transmission Crossmembers - 6-Speed Non-M

AAF E46 Radiator Fan Shroud

AAF E46 Transmission Crossmembers - 6-Speed M

Active Autowerke Thermostat Bypass/Delete Tube - S65

Active Autowerke Cnc Aftercooler Cooling Kit - F8x S55

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