2007 Mazda 3 GT 5 Door - Check Engine Light P0126 Error
 

Hey guys
Drove through some bad snow flurries over the weekend got a CEL which I checked today and came up P0126 (P0126 Insufficient Coolant Temperature for Stable Operation). I have no rough idle, no stalling *yet* and smooth running. Had a code reader and I cleared the CEL to see if this was a one off.

Light didn't come back on after driving home. Will drive tomorrow and recheck again.

I have an appointment with the mechanic to swap the Thermostat. Should I hold off to see if the CEL come back or just swap out the part?

Thanks

I had this happen to my 2007 5 door. I replaced the thermostat and cleared it out. Note that this is generally the thermostat being stuck open, much better than stuck closed (watch your coolant temperature to ensure it doesn't overheat).

With the weather getting warmer, you might get lucky, or you might find yourself clearing it out only for it to recur in a matter of days. It's best to just get it done, it won't fix itself - you'll just get lucky with the temperature for a while.

This is not an overly difficult job for a shade-tree mechanic, and there are videos out there if you want to take it on yourself. Cover your alternator, it sits right below the thermostat housing and will get drenched when removing the old thermostat.

Guess I will be good for a while with warm weather and notice it around fall time when the temperature starts to drop.

If I can hold off for now it will be good. Temps are great and fuel mileage has been better than normal actually.

Just happened to me last week on my 06 5door. I'm a YouTube mechanic and got the job done without much effort. A lot of instructional videos/advice will tell you to remove the pully tensioner and/or the belt to give you more space. I did it fine without having to do this step.