Mysterious Heater Issues

Hi! I’ve had this checked out twice by the dealer and once by another mechanic and they say there’s nothing wrong but please … I know my car (and my nose!). First symptom: the heater will start out hot but about a half-hour into my trip into work it significantly cools down. I’m not sure if it’s starting out too hot and cooling down appropriately but I think not … it gets downright cool at 70 degrees.
Second symptom: I sometimes smell coolant in the passenger compartment, usually while I’m operating the heater. However, in these last bitter cold days I’ve smelled it when I get into my cold car in the garage in the morning.
Third symptom: I have a film on the inside of my windshield on the lower one-sixth or so … it gets very cloudy, particularly when I circulate air to the windshield or turn on the AC to defog.
I’ve asked three times to have the heater core checked and they all say it’s fine. Any other ideas?

What year is the car? Do you have a temp gauge? Experiencing any coolant loss?

What year is you Accord, by the way?

Clearly coolant is leaking into the cabin. Did you show the windshield film to the dealer and the mechanic, and tell them about the smell? How did they tell you with a straight face that there was no problem?

The heater core may be leaking at such a small rate that it’s not obvious. But clearly something is leaking. The real mystery is why no one wants to help you. Find a recommended mechanic near you at the “Mechanics Files” section of this website, because the people you’ve already seen are apparently not interested.

Part of their reluctance may be that it’s a pain to remove the heater core and they just don’t want to deal with it.


You have the classic symptoms of a failed heater core

For some reason, your mechanic refuses to believe it. Or he is blind to all the symptoms.

Here’s what I recommend. Find a reputable shop. Tell them this “I am not paying to diagnose my car. I am paying you to replace the heater core and the thermostat. I will not hold you responsible if my problem is still present after the new heater core is installed.”

Good luck, and please post back with an update