07 explorer heat

Hello all! long time no see!

When fully warmed up, my heat does not come out unless the vehicle is in motion.
When I stop at a light, it blows cold, then when I accelerate, it gets hot again.

Thanks in advance to everyone!

-Chris

Does your Explorer have the manual HVAC controls or the electronic controls? Was any work performed recently that would have impacted the cooling system?

It sounds like you either have a vacuum issue that is allowing your heater control valve to close at idle (not sure if the 2007 uses that with the manual controls), there's an air pocket or low coolant level in the cooling system, or your water pump is not circulating the coolant properly.

-Rod

The more RPM's on your engine, the faster your water pump is pushing coolant through your Heater core.

It's probably time for both a radiator coolant system flush & heater core back flush.
Bench test your heater control valve and consider a new thermostat.

See damage from neglected coolant services, see AF www.automotiveforums.com/vbulletin/showthread.php?t=155214 (http://www.automotiveforums.com/vbulletin/showthread.php?t=155214)