I was wondering if anybody can help me out here, in November I was getting heat no issues but then I started to feel warm air and not hot air coming out the last few days here in canada where temperature got around -30C. I brought the car in to the garage and the mechanic touched the two rubber hose and said they were fine but to me one was hotter then the other, However they said I need a heating core and thermostat and a flush, I just felt they just said that and wanted to take my money. Today I felt the heater core lines the in and out rubber tubes and one was hotter then the other so I went ahead and flush the heating core with a garden hose and then air pressure the water out, stuff did come out but I would not say a lot of debris came out. I put everything back together and warmed the car up and felt the heater core rubber pipes and one still seems cooler then other however they are both warm so it's not like there is a big temperature change. I turned the heat full blast and it seemed there was warm air blowing again not hot but warm, I would say its warmer then what it was, now my question is do you think I need a new thermostat or heater core? On any giving day my temp gauge on the car does not reach to the half mark when idling or when driving it only reaches to the first line on the gauge even if has been idling for 20mins. Is there a way to verify if the thermostat needs to be replaced? If so is there any instructions on how to do this? Thanks