1999 Expediton running hot and no heat from vents.

[jstargell34]

I have a 1999 Ford Expedition AWD/4x4 4.6L engine. It is running hot. I do not have water in the oil or oil in the water. Does not have smoke coming from the tail pipe and runs smooth. I have replaced the water pump, thermostat, radiator, flushed the lines. I let it idle for 1 hour and it never ran hot but the heat never got hot inside the car. Also I drove it around the block and the engine ran hot. Had to pull over let it cool down then drove it back hot and it ran hot as I was pulling into the driveway. Help.

 

[jstargell34]

I changed the thermostat again today and it ran hot again and the heat will not get hot. I took the thermostat out and let it run straight and the car will idle wigthout getting hot but when I drove it again it ran hot again.

 

[stamp11127]

Did you burp the system when you removed the t-stat?
Do you have bubbles in the surge tank when running?
Have you checked the upper and lower rad hoses with a temp gun when running?
What color is the coolant in the surge tank?

 

[R0CK1TMAN]

I feel your pain. I just went through this myself:

I purchased a 1998 Expedition from a lot and on the day I bought it I was burning up hot so I just didn't try the heat, my mistake.
Within a few days I noted that the heat did not work. I also noticed the truck was "burning" coolant.
I took it back to the dealer to give him a chance to make it right and he turned me onto his mechanic who replaced the front and rear heater cores. One was partially clogged and the other completely.
I learned at that time that the engine coolant must freely flow through the motor as well as the heater cores to manage heat.
This fixed my heater problem but the vehicle would still over heat and developed a coolant leak.

The leak I fixed with K-Seal coolant system sealer and have had no overheating or heater problems since.

Wouldn't recommend K-seal if your car has resale value, but the alternative was $900-$1200 repairs vs. $14 mechanic in a bottle for a $1600 lemon was a no brainer.