Thanks for the update on yours, eiriksmil.
I live in Chicago and I noticed it a few months ago when it was 0 degrees F. I have a 15 DE 5 speed. I had 2 coats on, hat and gloves and I was still cold. I drove for an hour and was puzzled why my car was not getting heat. I looked around and checked my cabin filter and couldn't find anything.
I then found this thread and brought the car in to Mitsubishi. I told them to compare with a new car and see what the difference is between driver and passenger side on both cars. The temps were 20 degrees F to 30 degrees different from side to side.
They called tech line and ordered a new heater core (matrix). Upon re-assembly the tech noticed a hair line crack on the re-circulation door. They said it was preventing the heat form getting even hotter so they then had to order a new door as well. The dealer said there is an updated re-circulation door so I would ask about that if you are bringing your car in for a heater core.
They did an ok job but I wasn't impressed. They delivered the car with the firewall blanket soaked in coolant. Before I left the area I let the car run for 30 mins and low and behold I had a coolant leak the size of 6in diameter circle on the ground. Also I could see the heater core going through the firewall was wet.
I went back to the dealer and they readjusted the hoses on the heater and blew compressed air on the heater core hoses and blanket. I don't know if the leak was from the blanket or the hoses. I've been keeping an eye on the ground and the overflow bottle to make sure the level isn't changing when cold. I dropped it off Monday 10 am and left the dealer Friday at 2pm. I really was hoping I didn't have to bring the car in because once something is "fixed" its never as good as it was from the factory IMO especially on a big job like this. There are some scratches, smudges and what not but so far so good, no leaks and hot heat!
Suck squeeze bang blow!
My heat works, but my car has the symptoms of unequal heat from side to side. I'll definitely be taking my car in for this the first time it's cold next season. After next winter, my car will be out of warranty. As much as I don't want my dash removed, I really don't want to get stuck doing this job myself in a couple of years after the warranty runs out.
View my fuel log 2015 Mirage ES 1.2 manual: 51.4 mpg (US) ... 21.8 km/L ... 4.6 L/100 km ... 61.7 mpg (Imp)