I’ve installed Borg Wagner thermostats and those always failed until I installed a Mahle one which never failed. For some reason any other brand will get stuck open and the engine will never get up to temp.
I used Mahle, but I got lucky I got the German-made one (afaik now most are made in Italy). It was NOS so I expect the electrical heater (to open early) to be defect. It's been 3 years without issue though.
I used oem bmw coolant and a mahle thermostat.
The gasket looks fine. Normal procedure would be to buy a new one from BMW. always go OEM with the thermostat, there's a lot of shit knockoffs.
I had a brand new mahle one with the connector wired in reverse for constant. Kept blowing a fuse. Returned it for a replacement and worked fine.
Notice the radiator is leaking. Replace that. Car still not happy, cooling fans on full blast. Codes point to a thermostat, but the radiator hoses get warm. In my pea brain thermostats don't normally just sometimes go bad, they're typically either all broke or not broke. Ordered a thermostat from Trumplandia anyways.
Hatte auch schon ein Mahle Thermostat das kurz nach eimbau defekt war. Dannach ein Originales von BMW rein und seit dem wi3der keine Probleme.
I bought from FCP euro one of the OE water thermostat and water pump. The thermostat sticks open since new so I get check engine light on my M54 engine.
I have had brand new bmw thermostats not work and cause my car to get hot on the highway.
I bought a 2022 X4 about a month ago from BMW. Had it for 2 weeks and got the same notification. Took it to BMW ( I got the warranty) and adjuster came in from the warranty people on Monday but haven’t approved the repair yet. They said it was also a thermostat. Seems like this is a common thing in these cars ? Mine is at 61k miles, bought it used and only had it for 2 MF weeks.
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If choosing thermostat across many manufacturers, check the part ranking. If your choice is down to two brands, the PartReview part comparisons help.
We compare thermostat across these categories:
In March 2026 on PartReview, thermostat OEM BMW were overall better than Mahle.
Thermostat Mahle and OEM BMW were equally popular according to data in March 2026.
By vote balance, thermostat OEM BMW surpassed Mahle:
By number of reviews, thermostat Mahle surpassed OEM BMW:
In March 2026, according to PartReview, thermostat Mahle led more car-specific ratings than OEM BMW:
Mahle are chosen by owners of cars such as: Jeep Grand Cherokee, and others.
Thermostat OEM BMW have not yet taken leading positions in car-specific ratings. You can help by adding a review and specifying your car.
If this comparison didn’t fully answer your question, there are many others on PartReview.
For example, comparisons of thermostat Mahle with: MotoRad, Wahler, OEM Volkswagen, OEM Mazda, MOPAR, MISHIMOTO, Gates, OEM Nissan, OEM Audi, Duralast.
Also available: comparisons of thermostat OEM BMW with: MotoRad, Wahler, OEM Volkswagen, OEM Mazda, MOPAR, MISHIMOTO, Gates, OEM Nissan, OEM Audi, Duralast.
You can also see who is better among other thermostat manufacturers: Wahler or MotoRad, OEM Volkswagen or MotoRad, Mahle or MotoRad, OEM Mazda or MotoRad, MOPAR or MotoRad.
