WHEN STARTING CAR ONCE ENGINE WARM THE HEAT ...

2003 Mercury Sable

Tiny

Anonymous

January, 3, 2013 AT 11:25 PM

When starting car, once engine warm, the heat blows hot for a few minutes then start blowing cooler air.

FOUND 3513 RELATED QUESTIONS

1 Answer

Tiny

Wrenchtech

January, 3, 2013 AT 11:38 PM

With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both hot to the touch. If not too hot to hold, then you have to look at the actual engine temp and if that is up, if it is, then your looking at a restricted heater core.
If you find that they are both too hot to hold, then the heat in that vehicle is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.
If they are both not too hot to hold on to, then you either have a restricted heater core or the system is not completely full and getting air pockets for some reason.

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