The hot water/ heater control valve came apart on my 94 Explorer causing a massive loss of coolant and an engine overheat. I replced the valve, but when I took the truck out for a test drive it still ran very hot. Could the original problem have cooked the thermostat? Otherwise, I guess there is a chance that I connected the hoses backwards on the new valve...but I thought I put them back on the way they came off. The hose on the passenger side of the valve goes to the top of the engine, and the hose connected on the driver side goes to the bottom of the engine. Thanks for any ideas.

 

The valve has nothing to do with the overheating.

After you changed the valve & topped it off with antifreeze, did you let it idle with the radiator cap off to bleed the air out? Did the coolant overflow when you did this?

 

I suggest replacing the t-stat. That may be your original problem. If the tstat stuck, and it got hot, it may have just blown at the valve. T-stat is a cheap and easy replacement.

 

Yes.

I did go ahead and replace the thermostat. Seemed to solve the overheating problem. As usual, one bolt is a real PITA to get to, but that's nothing new.

One interesting twist. The temp gauge has always read real low for years. After changing out the heater valve and thermo, it now reads dead center. Anyone know where the sensor for the gauge is?

Thanks guys.

 

Do you mean it reads dead center once it's warmed up, or is it that way when it's cold as well?

 

Wamed up. Basically, the gauge is now operating the way it is supposed to. Before, it always read low.