Thermostat OEM Mazda or Motorcraft

I had the same issue, in the end, the thermostat was faulty, and the dealership replaced it for free. I didn’t have any warning light on the dashboard either.

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.

The Motorcraft thermostat sounds promising though, never have an issue with genuine ford parts.

I used a motorcraft RT-1139 thermostat. Comes with a jiggle valve to help bleed air already installed and cost me 8 bucks. You won’t find any place that says they fit other than some forum posts but they do indeed work, I installed one on my MJ with the only issue being me not refilling the radiator after dumping all the coolant.

I requested they use only Motorcraft thermostat, because I knew there was a part # update. Threw the updated Motorcraft one in and it solved the issue.

I replaced the thermostat from a non-OEM to Motorcraft about a month ago, and the only difference has been the speed at which the dial moves from higher temps to its normal positon.

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.

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

I bought a Motorcraft thermostat from the Ford dealer for my Crown Vic and it ran about 20 degrees cold.

Our 2022 CX-5 Premium Plus (non turbo) is going in for its 3rd thermostat replacement next week. Each time it’s been replaced at Mazda under warranty with an OEM part. Vehicle will hit 90,000 Miles this month. Does this thermostat wear seem excessive or is it normal for these? Bought brand new and it’s been the only problem, other then general maintenance