94 ranger, 2.3l

seem to have a cooling system flow problem. heat only works when driving vehicle... if I stop a light... the heat will go cool until we start moving again. opened the radiator cap to look at the fluid flow. you can see the fluid moving. When I rev the engine... the fluid level goes down in the radiator. when I return the engine to idle... the level comes back up... in fact it overflows...

any ideas?

thanks, rob

 

Sounds like a plugged heater core .

 

No. It sound like the cooling system has an air pocket. Have you recently done any repairs/mods in which you had to monkey with the cooling system?

If the core was PLUGGED it would not circulate at all. It could be that it is PARTIALLY plugged. Try removing the heater hoses at the Heater control valve and purchasing a back flushing t at a parts store, and back flushing through both sides. There will be junk to come out. You also want to ensure the control valve itself is fuctioning by testing the little valve on it.

Hope it helps.

Look up a how to on a coolant flush. Flush the whole system, and be sure to do the heater core sepertly. Good practice to replace thermostat and gasket while your at it.

 

Did you find your problem? I have the exact problem

 

your radiator core is plugged
take off your rad cap and wait till the thermostat opens
the coolant should rush into the rad.
if it just pools and the level rises ( your core is plugged )