View my fuel log 2014 Mirage DE 1.2 manual: 66.3 mpg (US) ... 28.2 km/L ... 3.5 L/100 km ... 79.7 mpg (Imp)
I know this is a bit old, but I wanted to pass on that I too now have a heater core that is leaking. I am waiting to see if Mitsubishi will cover the work under warranty, I currently have 65k miles.
Update: I just had the heater core replaced for the 3rd! Time, and neither the dealer nor Mitsubishi has a clue why it keeps failing. This last time, they even had a video conference with the tech guys in California, and everyone is just dumbfounded. Off the record, the service manager said it was a bad design; crimp on vs ring clamps. I was also told to trade it before the warranty expired, because based on the service record of the car, the heater core will fail again in 10 to 12k miles. I guess I'll take their advice, but I won't be buying another Mitsubishi Mirage.
Engine coolant based non-silicate, non-amine, non- nitrate and non-borate coolant with long life hybrid organic acid technology
Last edited by inuvik; 10-29-2017 at 03:46 AM.
View my fuel log 2015 Mirage ES 1.2 automatic: 40.6 mpg (US) ... 17.2 km/L ... 5.8 L/100 km ... 48.7 mpg (Imp)
I would assume that the dealership is using the correct antifreeze, right?
What about your radiator cap? If it isn't operating properly, maybe it could cause an over-pressure condition in the cooling system (with the heater core being the weakest point)? Or maybe a head gasket leak is introducing excess pressure into the system?
Does your car spend a lot of time idling in traffic? Put another way, does it often operate in the upper levels of the cooling system's acceptable temperature range?
Just thinking out loud...
I find it very hard to believe that there isn't something else going on with your particular car, as this seems to be a very rare problem for everyone...except you, unfortunately! Mine has nearly 80k on it and I haven't had any heater core trouble, nor have I had to add a drop of coolant since I bought it.