BMW Thermostats for BMW 3 Series E46 (1999-2005)

Replace the Achilles heel of your factory cooling system with a stout and reliable mechanical thermostat setup.

The factory E46 thermostat housing is a combined unit featuring a plastic housing and a built in thermostat that you cannot replace separately. These plastic all-in-one units are commonly know to crack or fail causing a headache, a trip on the tow truck and possible damage to your engine.

Taking cues from the reliable M50 thermostat setup we designed a an assembly that not only converts your plastic housing into a billet aluminum unit but also swaps out the integrated thermostat for a separate replaceable thermostat. The ability to swap out thermostats separately from the whole housing opens up doors to changing thermostats to different temperature ratings based on your application while also providing lower maintenance costs. No longer do you have to replace the whole housing but just the thermostat itself.

The billet housing is designed to be utilized with E46 M3 upper and lower radiator hoses and also features -16 ORB connections for custom radiator hoses. A major upgrade from the factory and aftermarket plastic units. Our thermostat housing kit can be used by the savvy daily driver or the track hero who wants to ensure the durability of their cooling system.

Key benefits:

Uses M50/S50 mechanical thermostat for increased reliability
Option to use aftermarket colder thermostats if desired
Thermostat can be replaced separately for lower maintenance cost
Barbed hose connections for use with E46 M3 hoses or built in -16 ORB connections for custom radiator hoses
Design:

Machined out of a single piece of billet 6061 aluminum, this thermostat housing will withstand higher prolonged temperatures and abuse for performance applications
Black anodized with engraved Turner logo on the front to match the Turner Motorsports Power Steering Reservoir
Viton gasket for superior sealing performance
For use with E46 M3 radiator hoses 11537830715 and 11537830716
Kit contents:

6061 Billet Aluminum Thermostat Housing
Mechanical Thermostat
Thermostat Housing Gasket
Thermostat Harness
Optional Silicone or Rubber E46 M3 coolant hoses
Product Development:

Our Billet Thermostat Housing upgrade was designed, engineered, tested and quality inspected by our Research and Development team at Turner. Nothing but the highest level of precision and quality through leading-edge product development technology including FARO laser scanning for reverse engineering and quality inspection, SolidWorks 3D CAD modeling, rapid prototyping utilizing our in-house 3D printer and rigorous long term product testing.

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 

The thermostat cover in your BMW, made from plastic, is notorious for failing. After years of exposure to hot coolant, the plastic can crack, leading to significant coolant leaks and potential engine overheating.

URO Parts offers a superior solution with their high-quality thermostat cover, designed to surpass the durability of the original factory part. This replacement thermostat comes complete with a gasket for an effortless service.

Features:

Perfect Fit: Guaranteed fitment ensures a seamless replacement process. Optimal Cooling: High-flow OE-style design ensures efficient engine cooling performance. Easy Installation: Manufactured to factory housing dimensions for straightforward bolt-on installation and secure hose connections. Comprehensive Design: Includes ports for temperature sensors where applicable. Superior Materials: Constructed from high-quality alloy or composite materials that resist temperature-induced warping or cracking, preventing coolant leaks. URO Parts, with over 8,000 premium spare parts, specializes in manufacturing precise, durable replacements for factory BMW components. Committed to the highest standards of precision, materials, and workmanship, each part is rigorously tested to deliver the best combination of durability, functionality, and affordability. For reliable replacement parts that offer great value, choose URO Parts.