Overheating

[Canyon Man]

Hello Boys,
So here is my problem. 2000 ford Expedition 5.4 is overheating. My coolant reservoir was only a bit low. I would drive it a few miles and the temp gauge would peg out. I would then wait about 5 min temp would be in the middle range and peg out in less than 30 sec when I would start it up again. I am blowing heat from the vents so my water pump is circulating.And after 30 miles of this cycling I never lost any more coolant (I had to get home from work). When I would pull over to the side of the road I could easily pull off the radiator cap and nothing would boil over at all. So could it be the sensor in the head? Maybe faulty? I didn't notice any unusual smoke from the exhaust. The truck does have 250,000 mile on it though.
Thanks for any help

 

[69Hcode]

Might be a stuck thermostat

 

[Canyon Man]

If the thermostat was stuck I wouldn't be getting hot air from vents, correct? Because with the heat on I am getting hot air.

 

[stamp11127]

Easiest thing to do would be to check the temp of the upper radiator hose, lower radiator hose and across the radiator. An ir temp gun is a good tool for doing this and cheap ones are under $40. You would be looking for cool spots on the above items.
Depending on the mileage I would consider changing the water pump just as a maintenance item & change coolant. If you mix your own make sure to use distilled water and not tap water.

 

[Yudaman]

If the thermostat was stuck I wouldn't be getting hot air from vents, correct? Because with the heat on I am getting hot air.

Wrong.
Ford uses a bypass from the upstream side of the thermostat to the heater core and then back to the water pump.
Change your thermostat.

 

[greasemonger]

When mine did this it was the water pump. Service tech showed me that my oem impeller fins had completely rusted away, thus not moving anywhere near the amount of pump action needed at speed. Cheap fix too and hasnt gone over 1/3 on the gauge since...but also change the tstat.

 

[Canyon Man]

Thanks a lot guys. I will check it all out this weekend. But I did change the pump and thermostat about 2 years ago

 

[IMINYOURCHAIR]

Thanks a lot guys. I will check it all out this weekend. But I did change the pump and thermostat about 2 years ago

thermostats fail... I usually go with what is called a "superstat" by stant. never had one fail but if they do it will stay open as a fail safe..

 

[Canyon Man]

Awesome. I will put that in

 

[Bedrck47]

Thanks a lot guys. I will check it all out this weekend. But I did change the pump and thermostat about 2 years ago

A lot can happen in two years