Help, ST is over heating

[Bas Jussen]

Dear all,

Our '01 ST is over heating and my wife had to put it on the side of the road. I checked for leaks, but there seem to be none (radiator is only about a year old, I also replaced the thermostat housing at the same time). The weird thing is that I filled the radiator up some more just in case, I took the truck for a test drive last night and the temperature just shot up after a few minutes. I took a right turn to go back home and than all of a sudden, the temperature went back down and stayed like that. I wonder what this could be. Waterpump maybe?



Greets,

Bas

 

[Yardsale]

Maybe. Thermostat?

 

[Vic Sorlie]

Description not clear - did you replace thermostat along with the radiator, or just the housing? Is coolant level holding or are you losing fluid?

 

[Doctor CAD]

Had the exact same symptoms last week. Temp normal, then just shot up to the top of the scale and my HOBDrive showed 257 degrees. I was in traffic, so I stuck it in neutral and gave it a bit of throttle to spin the fan and it dropped right back down to normal.. I watch ed it really closely for the next day or so, and it was quite erratic. Temp was all over the place.



I looked in the radiator and it seemed full, but the overflow bottle was empty. Added a half-gallon of Prestone pre-mix and the temp smoothed out a bit. After the test drive, I noticed the overflow was empty again, poured the other half gallon in and all is well again./



I think that the radiator sucked in a bubble of air (due to the overflow being empty) and if that bubble got near the temperature sensor, it would cause the temp to spike. Seems back to normal again.



Now...where did the full overflow tankful go??? No leaks, no burning, no smell inside the cab, etc.

 

[Ed Fenwick]

Aloha Bas, That sounds as though the thermostat is sticking. You could replace it or take it out and see if there is any crud holding it closed.

God bless Ed

 

[EddieS'04]

T-stat or fan clutch.....

 

[John G]

Thermostat.



The temperature that shoots up sporadically even though the fluid level is fine, that's the symptom my 2001 had a couple of years ago. That's how long the original thermostat lasted.

 

[Yardsale]

When mine went out (the original lasted a long time, too), it would run hot and the idle was high causing hard braking and odd downshifting. That's Ford's "crutch" mode - raise the idle to pull more air over the radiator.