Thermostat OEM BMW or OEM Mazda

I have this exact engine and installed a diesel thermostat. Previously, with the standard thermostat, the plastic timing chain guides would start to disintegrate after three years, but now I have no problem with that. The engine temperature is around 96°C.

I had the same issue on my 09 Mazda 2.3L. Everything looked good on the dash, but the thermostat let too much coolant through, over cooling the engine. My CEL came on, I reset it, and it reappeared. Long drives on the freeway in cool weather was the scenario that triggered it, as the radiator is very effective at speed, and the engine isn't working hard cruising on level ground at freeway speeds. I bought the thermostat "cover" (it's the plastic assembly with the thermostat integrated in it-- PN LF70-15-170) for $57 from Amazon and installed it last November and the CEL has not reappeared.

Thermostat is an bmw part so its fine

03’ E46 318ci with 130k miles and no issues with the whole cooling system. Neither the thermostat.

I was instructed by a friend who had some of m47 and m57, to buy thermostat only original from bmw, because everything else doesn't work as long or good.

Always buy the Mazda OEM branded thermostat from any local or online Mazda factory parts retailer, this is not the item you want to save a couple bucks on, no matter how much you trust that ‘other’ brand.

They kept it for another day and were obviously able to replicate the fault and replaced the Thermostat as they thought it was sticking causing the Temps to fluctuate.

Thermostat failed multiple times

I just had the code P0126 on my 2021 mazda cx-30 with 20,000 miles. Seems to be the same issue

I replaced the t-stat with a genuine part and again no luck.