Thermostat Wahler or OEM Mazda

I narrowed it down to a bad thermostat and bad radiator. I ordered the OEM Mazda parts for $450.00

In the past and up to several months ago, I’ve always gone with Saleri (Italy) pumps and Wahler (Germany) thermostats for the M54 and have had great results.

Some of the newer Mazda Skyactives have thermostat issues, but it's a minor problem (only symptom is taking longer to warm up) and Mazda extended the warranty on them. It's the only issue I've brought the car to the dealer for on my 21 Mazda 3 without roughly 50k on it.

I have the ‘19 CX-5, live in NH. Seems normal to me, when it’s below zero outside and the at idle, it should not be hot. Warm after 5-10 yes, but not warm as it would be after driving for 10 minutes.

Common for the thermostat and/or coolant control valve to fail on newer Mazda 3s. It's not a big deal but you might have more coolant loss and it takes longer to warm up.

Batteries crap and so is the thermostat / heat and the trim on the steering wheel and gear shifter is thin and cheap and will come off everything else. Car is great

I just got this fixed at the dealer on my 21. Its the thermostat. They put in over a million bad ones and don't want to own it with a recall so they sent out a TSB. There's also an extended warranty for all the cars for this part/labor.

I replace thermostat even the whole block. Same issue. This fucking car don’t heat.

I recently changed the thermostat on my dad's car as well, I went with a wahler, and I'm observing the same things.

That's due to their faulty thermostat for which they don't want to assume responsibility and call it what it is - a recall.