my 1992 honda accord has been overheating lately. We checked the coolant and it was fine, we don't have a radiator leak. I was going to change the thermometer but someone had told me not to because when you turn the heat on to take heat off of the motor the temp gage goes hotter. and when you apply gas it goes down (as in I have a manual and just applying gas when stopped. Someone told me it was the heater core. I was just wondering if that's correct of if you have any suggestions.