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

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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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Thermostat Replacement Kit - E46 M3
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:554082
Part#: 11531318274KT2
In Stock
$ 139.99

This product was last offered at the strikethrough price on
07-16-2026

$ 87.99 USD
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$ 87.99 USD
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When it comes time to replace your thermostat, be sure you have everything you need. This kit includes everything you need to replace your thermostat, including the thermostat.

Kit includes:

  • Thermostat
  • Thermostat O-Ring
  • 1.5 Liters of coolant

 

This item fits the following BMWs: 
2001-2006 E46 BMW M3 

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Packaged by Turner - Corporate Logo
T#:554073
Part#: 11537509227KT3
Ships on Feb 22, 2027
$ 103.99 USD
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$ 103.99 USD
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When it comes time to replace your thermostat, be sure you have everything you need. This kit includes everything you need to replace your thermostat, including the thermostat.

Kit includes:

  • Mahle-Behr thermostat with gasket
  • Thermostat mounting hardware
  • 1 liter of coolant

Applications:
1999-2003 E39 528i, 525i, 530i sedan, touring wagon (M52TU engine, M54 engine)
1999-2005 E46 323, 328, 325, 330 sedan, coupe, cabrio, touring wagon (M52TU engine, M54 engine)
2004-2005 E60 525i, 530i sedan, touring wagon (M54 engine)
2001-2006 E53 X5 3.0 (M54 engine)
2004-2006 E83 X3 2.5i X3 3.0i (M54 engine)
1999-2002 Z3 2.3. Z3 2.5i, 2.8 Z3 3.0i (M54 engine)
2003-2005 Z4 2.5i, Z4 3.0 (M54 engine)

 

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Cooling System Refresh Kit - Level 1
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:15744012
Part#: 32411712735-KT
In Stock
Sale - Save 7% $ 664.99

This product was last offered at the strikethrough price on
07-16-2026

$ 619.41 USD
Free Shipping on orders $49 and up
Sale - Save 7%
$ 664.99

This product was last offered at the strikethrough price on
07-16-2026

$ 619.41 USD
Free Shipping on orders $49 and up
Stop the problems before they arise. If you vehicle has 60,000 miles or more, replace all of these components to ensure that your vehicle stays healthy. To keep everything in top order, continue to replace these components at 60,000 mile intervals. Water pump failure, cracked plastic housings, and expansion tank leaks will not be a concern once all these problem parts are replaced. Included in this kit are the following parts. Rein Water Pump with metal impeller FAE Fan Switch Vaico Q+ thermostat - made in Germany! New O-ring Sealing Gaskets OEM Expansion Tank & Cap 1 Gallon Coolant Rein Upper & Lower Radiator Hoses
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Bav Auto Thermostat With Aluminum Housing - M52TU M54
10X Entries Into Our F80 M3 Sweepstakes
Bavarian Autosport - Corporate Logo
T#:12544802
Part#: 11531437040
In Stock
Sale - Save 19% $ 104.99

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

$ 84.99 USD
Free Shipping on orders $49 and up
Sale - Save 19%
$ 104.99

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

$ 84.99 USD
Free Shipping on orders $49 and up
The plastic thermostat cover in your BMW is a known point of failure. Throughout years of repeated contact with hot coolant, the plastic can crack and cause massive coolant leaks and potential overheating. Eliminate one of the weak links in your cooling system with a replacement aluminum thermostat housing. By installing this aluminum unit, you have no worries as far as plastic housing cracks go
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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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Mishimoto - Corporate Logo
T#:640347
Part#: MMTS-E46-99V2
Ships in 3 Business Days
$ 135.99 USD
Free Shipping
$ 135.99 USD
Free Shipping

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.