Where is the heater control valve at on a 1998 Expedition (4.6). thanks

 

There's a heater control valve?

 

I do not think most Ford's have one. I think coolant flows thru the heater core all the time.

Maybe better than having coolant just sit in the heater core all during warmer months

 

I don't believe there is a control valve per se. The engine coolant is always circulating throughout the system and the infamous blend door controls the heat or cooling you get in the cabin of the truck. I believe there is a vacuum operated valve on the F250's and Excursions, but not sure. You may have to repair the blend door and there are many posts regarding this.

 

Thanks for the replies, I have found outt hat there is no HCV and I have already visualy inspected the blend door and it works good. I believe i am going to think i have a clogged heater core and/or line. thanks

 

You might try reverse flushing the heater core to clear it. Have you ever used any kind of radiator stop leak stuff in your truck?

 

no I have not use any kind of stuff like that, I will do the flushing and see what comes of it. With the rear unit, is there anything to do or should i flush the whole deal for the heat in rear is alittle warmer than front but nothing you would want to be in a long time in the winter in the new england area. thanks

 

I would try flushing the whole system with plain water. I am not a fan of the corrosive radiator flush products as they can cause even bigger problems. It could be something as simple as a blockage at the hose connection at the engine or in the hose itself.

 

Thanks