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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Mishimoto - Corporate Logo
T#:363172
Part#: MMTSE3692
In Stock
$ 68.99 USD
Free Shipping on orders $49 and up

The thermostat regulates the temperature of your coolant. At a predetermined temperature the thermostat will open to let coolant flow to the radiator and be cooled by airflow or the fan. Over time the thermostat will become stuck open or closed, leading to a variety of issues. A closed thermostat will never allow the coolant to reach the radiator and be cooled. Hot coolant will continue to circulate through the engine and absorb even more heat until boiling and the system overheats. An open thermostat is not as bad but is still not ideal - the coolant is always cool, with the temp needle always reading in the cool range. This tells the ECU to richen the fuel mixture to bring the car up to normal operating temp. So your fuel mileage decreases and the car runs rich.  

Replacing the thermostat is an easy but messy job. This thermostat includes the main o-ring (but a housing gasket may be required). Consider replacing the housing and any associated temp sensors while you're in there. The cooling system will need to be bled after.  

Most of the engines from the mid-1980s through the 1990s use the same thermostat design and they are interchangeable among the different temperatures. This is the 68*C thermostat, at the bottom of the temperature range. It should only be used in racing situations such as when deleting the engine fan. However, keep in mind that BMW spent a lot of time engineering the cooling system to work in all kinds of conditions and changing thermostat temperature is not recommended to fix any failures in the cooling system.  

Mishimoto makes coolant tanks, radiators and much more for your Mini/BMW. Established in 2003 their commitment to absolute quality in the aftermarket world is evident through the quality and performance enhancing products they offer.
 

This thermostat fits the following BMWs:   
1977-1983  E21 BMW  323i  
1986-1991  E30 BMW  318is 318ic 325e 325es 325i 325ic 325is 325ix  
1992-1999  E36 BMW  318i 318is 318ti 318ic 323is 323ic 325i 325is 325ic 328i 328is 328ic M3  
1982-1988  E28 BMW  528e  
1986-1988  E28 BMW  535i  
1989-1995  E34 BMW  525i 535i  
1997-1998  E39 BMW  528i  
1986-1989  E24 BMW  635csi  
1988-1994  E32 BMW  735i 735il  
1997-2000  Z3 BMW  Z3 2.8 M Roadster M Coupe 

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Bav Auto Radiator Hose - Lower - E46 M52 M54
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:640203
Part#: 11531436408
In Stock
Sale - Save 16% $ 36.99

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

$ 31.20 USD
Free Shipping on orders $49 and up
Sale - Save 16%
$ 36.99

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

$ 31.20 USD
Free Shipping on orders $49 and up
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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Mishimoto - Corporate Logo
T#:29002063
Part#: MMOC10
In Stock
$ 126.99 USD
Free Shipping on orders $49 and up

BMW & MINI Universal Oil Cooler - 10 Row is a versatile cooling solution designed to enhance the performance and reliability of BMW and MINI vehicles. This high-quality oil cooler provides efficient cooling for the engine oil, ensuring optimal operating temperatures and extending the life of vital engine components.

Crafted with precision engineering and durable materials, the BMW & MINI Universal Oil Cooler - 10 Row is compatible with a wide range of BMW and MINI models, offering versatility and ease of installation. It effectively dissipates heat from the engine oil, reducing the risk of overheating and engine damage.

  • Enhances performance and reliability of BMW and MINI vehicles
  • Efficient cooling for engine oil, ensuring optimal operating temperatures
  • Extends the life of vital engine components
  • Compatible with a wide range of BMW and MINI models
  • Versatile and easy to install
  • Crafted with precision engineering and durable materials

Investing in the BMW & MINI Universal Oil Cooler - 10 Row is a smart choice for BMW and MINI owners looking to improve their vehicle's performance and longevity.

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Advanced Auto Fabrication - Corporate Logo
T#:7608839
Part#: 11641
In Stock at Vendor
$ 189.00 USD
Free Shipping on orders $49 and up

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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Mishimoto - Corporate Logo
T#:51075091
Part#: MMWP-M50-92
In Stock
New Item
$ 72.99 USD
Free Shipping on orders $49 and up
The Mishimoto Performance Water Pump provides the thermal stability required for modified engines.
Mishimoto - Corporate Logo
T#:31291020
Part#: MMOC10BK
In Stock
$ 126.99 USD
Free Shipping on orders $49 and up

Universal Oil Cooler Black - 10 Row is engineered to maintain optimal oil temperatures and ensure peak engine performance under various driving conditions. This high-performance oil cooler effectively reduces oil temperatures, preventing a drop in pressure and maintaining proper engine lubrication. Featuring a robust 10-row design, it offers superior cooling efficiency compared to standard coolers.

  • Efficient Cooling: The 10-row design enhances cooling capacity to manage high oil temperatures effectively.
  • Durable Construction: Black finish provides durability and resistance to environmental factors.
  • Optimized Performance: Helps prevent a drop in oil pressure and maintains proper engine lubrication.
  • Versatile Fitment: Universal design suitable for various vehicles and applications.
  • Compact Size: Overall dimensions of 12.95" x 3.8" x 1.97" and core dimensions of 11" x 2.76" x 1.97" ensure a good fit in most engine bays.

WARNING! Prop 65 may apply to this product. Proposition 65 (Safe Drinking Water and Toxic Enforcement Act of 1968) is a California law that applies to all companies selling products in California. Prop 65 requires any listed chemical present above very low levels that are known to cause cancer, birth defects, or other reproductive harm. For more information about California Prop 65 warning see: www.P65Warnings.ca.gov.

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Mishimoto - Corporate Logo
T#:51075086
Part#: MMTS-E46-99E
In Stock
New Item
$ 91.99 USD
Free Shipping on orders $49 and up
The Mishimoto Thermostat Assembly focuses on precision fitment and long-term durability.
Mishimoto - Corporate Logo
T#:19593926
Part#: MMOCULT
In Stock at Vendor
$ 599.99 USD
Free Shipping on orders $49 and up

Enhance your BMW's performance and protect its engine with this high-quality oil cooler kit

Even under ideal driving conditions, elevated oil temperatures can lead to decreased lubrication efficiency and pressure. With this oil cooler, you can maintain optimal oil temperatures for peak driving performance.

Kit Includes:

  • Four feet of stainless braided line for durability
  • Adapter fittings for easy installation
  • Oil filter sandwich adapter for seamless integration

Specifications:

  • Rows: 19
  • Overall Dimensions: 13" x 5.5" x 2"
  • Core Dimensions: 11.25" x 5.5" x 2"
  • Braided Hoses: 4ft .75 inch & 4ft 9 inch
  • Braided Hose Fittings: -10AN
  • Sandwich Plate Fittings: -10AN
  • Includes Thermostat for precise temperature and flow control

*WARNING: This product may be subject to Proposition 65 regulations in California. For more information, visit www.P65Warnings.ca.gov.

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Mishimoto - Corporate Logo
T#:27938415
Part#: MMFSE4699
In Stock at Vendor
9% off MSRP $ 374.00

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

$ 339.95 USD
Free Shipping on orders $49 and up
9% off MSRP
$ 374.00

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

$ 339.95 USD
Free Shipping on orders $49 and up

Mishimoto - Corporate Logo
T#:363171
Part#: MMFANMOUNT
In Stock
$ 15.99 USD
Free Shipping on orders $49 and up
The Mishimoto universal fan mount kit is used to mount a Mishimoto electric fan to any Mishimoto aluminum radiator. Great for custom applications, the Mishimoto fan can be mounted in any convenient position on the radiator. Universal fan mount fits any Mishimoto electric fan Ideal for custom applications Mounts fan in any convenient position Mishimoto Lifetime Warranty
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