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
BMW E46 M54 AAF Low Temp Thermostat Kit - Partial
Advanced Auto Fabrication - Corporate Logo
T#:7624632
Part#: 116211.2
Ships in 2 Business Days
$ 85.00 USD
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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
AAF Transmission Crossmembers 5-Speed - E46 Non-M
Fits ZF and Getrag Transmissions. Non-M models Only
Advanced Auto Fabrication - Corporate Logo
T#:7608860
Part#: 116110
In Stock at Vendor
$ 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 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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AAF Low Temp Thermostat Kit - Full Kit - E46
AAF Low Temp Thermostat Kit - Full Kit - E46
Advanced Auto Fabrication - Corporate Logo
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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BMW E46 AAF Aluminum Radiator Mounting Kit
BMW E46 AAF Aluminum Radiator Mounting Kit
Advanced Auto Fabrication - Corporate Logo
T#:7608839
Part#: 11641
In Stock at Vendor
$ 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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DO88 Racing Oil Cooler - E46 M3
DO88 Racing Oil Cooler - E46 M3
DO88 - Corporate Logo
T#:13891842
Part#: OC150
Ships on Sep 18, 2026
$ 749.99 USD
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$ 749.99 USD
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With a 185% bigger core volume, 50% bigger cooling area, and a 79% higher oil volume, this oil cooler compensates on no fronts. Built for the track but just as capable on the road, DO88's upgraded oil cooler for the E46 M3 gives you maximum performance and compromises nowhere.
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AAF E46 Transmission Crossmembers - 6-Speed Non-M
AAF E46 Transmission Crossmembers - 6-Speed Non-M
For use with solid front engine mounts only!
Advanced Auto Fabrication - Corporate Logo
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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DO88 Racing Auxiliary Oil Cooler - E46 M3
DO88 Racing Auxiliary Oil Cooler - E46 M3
DO88 - Corporate Logo
T#:13891851
Part#: OC120E46
In Stock
$ 646.99 USD
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$ 646.99 USD
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This racing oil cooler shines in low-pressure situations, for example, power steering oil cooling or gearbox oil cooling. This oil cooler comes ready to install with hardware.
AAF E46 Radiator Fan Shroud
AAF E46 Radiator Fan Shroud
Advanced Auto Fabrication - Corporate Logo
T#:7624641
Part#: 116251
In Stock at Vendor
$ 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
AAF E46 Transmission Crossmembers - 6-Speed M
For M Models
Advanced Auto Fabrication - Corporate Logo
T#:7624640
Part#: 116223
Ships in 4 Business Days
$ 190.00 USD
Free Shipping
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$ 190.00 USD
Free Shipping
Add to Wish List
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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Aluminum Radiator - Black - E46 M3
Aluminum Radiator - Black - E46 M3
DO88 - Corporate Logo
T#:13891809
Part#: WC310S
Ships on Sep 18, 2026
$ 735.99 USD
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$ 735.99 USD
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The team at DO88 has vigorously tested this radiator to deliver peak performance with the peace of mind of quality for your E46 M3. They guarantee reliability and endurance in all situations to let your car breathe better than before! Boasting a 17% increase in core volume, this upgrade is a no-brainer for petrol heads like us. Keeping core temperatures low eliminates the risk of heat soak leading to overheating giving you max performance at any given moment. no compromise has been made at DO88 leaving you with one of the best radiator options on the market!
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Coolant Hose Refresh Kit - Black - E46 320/323/325/328
Coolant Hose Refresh Kit - Black - E46 320/323/325/328
DO88 - Corporate Logo
T#:14155765
Part#: KIT219S
Ships on Sep 18, 2026
$ 360.99 USD
Free Shipping on orders $49 and up
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$ 360.99 USD
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These hoses are entirely manufactured in high-quality silicone for best finish and durability. With three to five layers of armory, depending of the inner diameter, the hoses withstand high-pressure rates and high temperatures for a long time. The original hoses are manufactured in rubber that not seldom cracks from age. This is the durable solution for you that in addition improves the looks!
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Aluminum Radiator - Red Hose - E46 M3
Aluminum Radiator - Red Hose - E46 M3
DO88 - Corporate Logo
T#:13891810
Part#: WC310R
Ships on Sep 18, 2026
$ 735.99 USD
Add to Wish List
$ 735.99 USD
Add to Wish List
The team at DO88 has vigorously tested this radiator to deliver peak performance with the peace of mind of quality for your E46 M3. They guarantee reliability and endurance in all situations to let your car breathe better than before! Boasting a 17% increase in core volume, this upgrade is a no-brainer for petrol heads like us. Keeping core temperatures low eliminates the risk of heat soak leading to overheating giving you max performance at any given moment. no compromise has been made at DO88 leaving you with one of the best radiator options on the market!
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DO88 Coolant Hoses - Black - E46 M3
DO88 Coolant Hoses - Black - E46 M3
DO88 - Corporate Logo
T#:13924829
Part#: DO88KIT70S
Ships on Sep 18, 2026
$ 256.99 USD
Free Shipping on orders $49 and up
Add to Wish List
$ 256.99 USD
Free Shipping on orders $49 and up
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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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DO88 Aluminum Radiator - Blue Hose - E46 M3
DO88 Aluminum Radiator - Blue Hose - E46 M3
DO88 - Corporate Logo
T#:13891811
Part#: WC310B
Ships on Sep 18, 2026
$ 735.99 USD
Add to Wish List
$ 735.99 USD
Add to Wish List
The team at DO88 has vigorously tested this radiator to deliver peak performance with the peace of mind of quality for your E46 M3. They guarantee reliability and endurance in all situations to let your car breathe better than before! Boasting a 17% increase in core volume, this upgrade is a no-brainer for petrol heads like us. Keeping core temperatures low eliminates the risk of heat soak leading to overheating giving you max performance at any given moment. no compromise has been made at DO88 leaving you with one of the best radiator options on the market!
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DO88 Coolant Hoses - Blue - E46 M3
DO88 Coolant Hoses - Blue - E46 M3
DO88 - Corporate Logo
T#:13924830
Part#: DO88KIT70B
Back Ordered
$ 256.99 USD
Free Shipping on orders $49 and up
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$ 256.99 USD
Free Shipping on orders $49 and up
Add to Wish List
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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