Thermostat MISHIMOTO or OEM Mazda

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.

I have a mishimoto thermostat with their radiator setup. It does kick on the fans on at a lower temp range than when the stock one would which is good. I had issues running hot on the stock rad/thermostat and haven't had any issues since.

Make sure you use a Mazda OEM thermostat. I wouldn’t trust anything but OEM for those.

I replaced the thermostat with a Mishimoto thermostat and vaccume filled the coolant. I did a 30 min test drive in the 95+ weather with the AC cranked. Never went past the 7th dot.

My 2021 Mazda3 Turbo has classic thermostat failure symptoms: \n\n- Erratic warm-up (sometimes stuck cold, sometimes near overheating). \n- Upper radiator hose stays lukewarm even after 20+ mins of driving (revved to 3K RPM to test). \n- Housing burns hot, but hose never gets scalding\u2014clear sign of a stuck thermostat.

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.

Forget about the Mishimoto thermostat. The OEM thermostat is way more reliable and does the job.

I put the mishimoto 160* in hot water to test it out. Lo and behold, wax started seeping out.

I had 2 fail back to back. The first lasted 3 months, a couple thousand miles, the 2nd lasted 5 weeks, also a couple thousand miles. Left me stranded. 275 degree spike followed by coolant puking.

Thermostat failed multiple times