64 votes
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.
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.
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.
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
Thermostat failed multiple times
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.
I just had the code P0126 on my 2021 mazda cx-30 with 20,000 miles. Seems to be the same issue
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.
Make sure you use a Mazda OEM thermostat. I wouldn’t trust anything but OEM for those.
Buy an OEM thermostat from Mazda. The aftermarket ones are sometimes not identical.
Write your review about thermostat OEM Mazda
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