Heater Core Question

[keithaba]

I posted previously about the heater core possibly going on my 96 ford mustang.

I was just curious if any of the mechanically inclined could answer another question.

If the heater core is fooked, would the heat still work? I noticed that both the heat and the AC work fine. They just only come out of the dash (defrost setting) regardless of weather I set it to the vent, floor, mix....

Also noted, that the heat and the AC don't cause the windows to fog at all, until the engine gets hot (about 15-20 minutes of driving).

Does that rule out possible heat core?

The only reason I'm asking is because I am going to sell the car, and I don't want to be a dick and not tell the potential buyer that it might have a problem. However, I'm not 100% sure that's what it is, so I don't want to tell them incorrect info.

Thanks.

 

[wfooshee]

Failure to select the correct vents is usually a broken vacuum connection to the manifold. Some cars use electric motors to move the baffles, some use direct mechanical levers from the dash selector, but most use vacuum servos. If there's no vacuum, you can't select the vent. Most vacuum system default to defrost, as you've discovered.

None of that has anything to do with the actual condition of the heater core. The misting is from the high humidity caused by the leaking heater core. As the engine warms, the cooling system water gets hot and is pressurized. That's why it doesn't mist until it's been running a while - it has to warm up enough to build the pressure, and then the air blowing through the heater core picks up water vapor as well as the heat it's supposed to get, and carries it into the cabin.

It's conceivable that the leaking/misting has corroded the vent baffle hardware, freezing them in place.