2.8L Heater Not Working

[d-dog]

My son and I are stumped with his 85 Bronco II - the heater has quit getting hot. Pulled the two hoses off the heater core. The core is clean and clear. BUT, when the engine is running, no water seems to go to the core. The engine gets up to normal temp, but still no water goes from the top heater hose to the core, unless the motor is revved up. When it's revved, very hot coolant comes out, but only then. The motor doesn't overheat, and the thermostat seems to be working properly. When I sqeeze the large top radiator hose it will force some water out the heater hose so I know there's no restriction. HELP!! Any ideas is appreciated.
Thanx

 

[snake]

This may sound stupid, but is the radiator full? Just a few inches down will cause this exact scenario.

 

[timster]

did they have that heater switch thingy on the 2.9? I know explorers have it, and some rangers. Follow the heater hose from the radiator to the heater core if there is a little device that the coolant flows through, check that thing.

here is what it looks like
http://shop.advanceautoparts.com/Pr...=FAA&MfrPartNumber=74809&PartType=394&PTSet=A