BMW Thermostats for BMW 5 Series E34 (1987-1995)

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BMW thermostats are known to fail, but luckily they typically fail wide open - meaning that your car can still cool. We offer thermostats from various OE suppliers we trust along with upgraded motorsport specific thermostats where applicable to make sure your BMW stays cool on track.
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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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Active Autowerke - Corporate Logo
T#:397222
Part#: 14-009
Ships on Oct 23, 2026
$ 56.99 USD
Free Shipping on orders $49 and up
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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Rein Thermostat - 88�C - E30, E34, E36, Z3
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:591800
Part#: 11537511580
In Stock at Vendor
$ 37.99 USD
Free Shipping on orders $49 and up
Common point of failure in the cooling system.

Rein - Corporate Logo
T#:591144
Part#: 11531265084
Ships in 4 Business Days
$ 2.99 USD
Free Shipping on orders $49 and up
This O-ring seals the thermostat to the cylinder head.

Rein Thermostat 80C - E30 325e, E28 535i, E24 633CSi
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:34114243
Part#: 11531710953
In Stock
$ 19.99 USD
Free Shipping on orders $49 and up

Thermostat 80C is a crucial component for controlling the temperature in BMW engines, ensuring optimal performance and protection. Designed to open at 80°C, this thermostat helps your engine reach its ideal operating temperature quickly while preventing overheating. Engineered specifically for BMW vehicles, the Thermostat 80C ensures precise temperature regulation, enhancing both engine efficiency and longevity. Available at Turner Motorsport, this direct-fit replacement offers easy installation and reliable performance.

  • Designed for BMW engines for a perfect fit
  • Opens at 80°C to regulate coolant flow and maintain optimal temperature
  • Prevents overheating and improves engine efficiency
  • Manufactured from high-quality, durable materials for long-lasting use
  • Direct-fit replacement ensures hassle-free installation
  • Enhances overall engine performance and longevity

The Thermostat 80C from Turner Motorsport is the perfect choice for BMW owners looking to maintain optimal engine temperature, ensuring smooth operation and extending the life of their vehicle.

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