I have a 1998 f150 4.6L ext cab 4x4. i just bought the truck and there was a new heater core install before i bought it. it was installed by a ford dealer. when i start the truck i hear coolant flowing through the heater core until the truck warms up. is this normal? the coolant level is full. thanks for your help

 

Does it oveheat or anything? could be an air pocket but I kind of doubt it cause it would be overheating like crazy. Maybe you are hearing something else or have very sensitive hearing.

 

does the heat work well?? is it leaking coolant?? if not then i say leave her alone.

 

it does not overheat. heat works well. it just sounds like it might be low on coolant. it just sounds like water running through the heater core. the reservoir is full hot or cold. i only hear it when the truck is cold. thanks

 

You need to bleed the system if you want it to operate correctly - bleeding is done through the AC vent on your model.

 

how do you bleed the system? is that the cap that is attached to the line going to the heater core under the hood? thanks

 

Bleeding

Select maximum heater temperature and blower motor speed settings. Position control to discharge air at A/C vents in the instrument panel .

Start engine and allow to idle. While engine is idling, feel for hot air at A/C vents.

CAUTION: If the air discharge remains cool and the engine coolant temperature gauge does not move, the engine coolant level is low in the engine and must be filled. Stop the engine, allow to cool and fill the cooling system as described. Start the engine and allow to idle until normal operating temperature is reached. Hot air should discharge from the A/C vents. The engine coolant temperature gauge should maintain a stabilized reading in the middle of the NORMAL range and the upper radiator hose should feel hot to the touch.

Shut the engine off and allow it to cool.

Check the engine for coolant leaks.

Check the engine coolant level in the degas bottle and fill as necessary.

 

i done what you suggested and everything seams to be ok except for the top radiator hose is cold. which tells me that the thermostat is not opening. any thoughts?

 

Replace the thermostat?

 

Mine does the same thing. Sounds like it is bubbling inside the dash. I had the full system flush at the oil change center. Its better than before and maybe not as bad in the winter than the summer. I read that GM has a heater core specific cleaner, wonder if FORD has the same?