Heater core failure
Heater core failure at 75k.
Bypassed it and ran it this past summer. Looped a piece of 5/8 hose.
Coolant temps very stabil with core bypassed, AC works better also. Warm up time reduced as well.
New core is in now. Mitsu flat rate is 7hr. Guy who did it said he'd rather do 7 of these than one Chevy Equinox.
I will pressure test old core, suspect leak was from the pipe / core junction crimp.
Also suspect the very short heater hoses transmit movement to the critical pipe / core joint on this car.
Especially on the manual trans cars.
Will be making up some longer, looped hoses to isolate heater core pipes from engine movement. Also considering a bypass for next summer.
On the plus side, I did become adept at managing interior weather conditions through this experience.
Very happy to have warm toes again now.
__________________________________________
View my fuel log 2014 Mirage ES 1.2 manual: 47.7 mpg (US) ... 20.3 km/L ... 4.9 L/100 km ... 57.3 mpg (Imp)