BMW Thermostats for BMW Z Series E85/6 (2003-2008)

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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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Bav Auto Thermostat With Aluminum Housing - M52TU M54
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
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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Racing Thermostat - 70C
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Mishimoto - Corporate Logo
T#:640347
Part#: MMTS-E46-99V2
In Stock at Vendor
$ 135.99 USD
Free Shipping
$ 135.99 USD
Free Shipping
Mishimoto 74 Degree Performance Thermostat - N52 N54 N55
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Mishimoto - Corporate Logo
T#:363461
Part#: MMTS-E90-07
In Stock
$ 83.99 USD
Free Shipping
$ 83.99 USD
Free Shipping

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.  

For vehicles with plastic thermostat housing 

  

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