Check the coolant for exhaust gases, could be a head gasket issue.

 

When the engine is at operating temps or when it over heats the next time. ( by using your hand with engine NOT running ))See if the fan blade turns freely or if it will turn with a lot of resistance, if it will turn at all. If it is free wheeling the fan clutch is bad. The fan clutch locks the fan so that it turns 100% of the time the engine is running when the engine is hot.

 

Is the truck really overheating or do you just have a bad sending unit or faulty gauge/cluster? An engine doesn't cool down in 5 minutes unless its way below zero outside, and even then not quite that quick.

 

When ive had vehicle low on coolant, it can go hot to cool fast. Ect measures coolant temp, not engine temp. Coolant not circulating well or circulating with lots of gas can get hot fast, and cool down fast when circulation restored.

Make sure have good reservoir cap, refill coolant, and keep good eye on it while troubleshoot other stuff. If you had coolant overflow.....it takes another problem, or high enough temps your heads are likely toast now anyway.

 

MBB...we are talking physics here. Even if there is gas in the fluid, temp can't be changed enough simply by short breaks. The engine temp (metal and water and oil) can only lower so much in such a time and temps would come right back up.. If it's mechanical, it should do it every time. Not just whenever.

Still no one answered the question. Is it really overheating or is it possibly the sender or gauge system.

 

I'm not an expert but I'm leaning twords the sensor that measures the coolant temp, solely because I find it hard to believe an engine cool's down in 5 minutes.

 

Up here in AK, no good reputable shop will install an aluminum thermostat anymore. With cold/hot temps that can be really varied, most found out that the aluminum ones would tweak from the quick cooling and cold temps. They would bind, either not opening or not closing. They became a real comeback problem for a while. The Stainless Steels ones have no problems what so ever, and aren't that much more than the cheap, easily bent alum ones. I only buy SS ones anymore. I've seen too many Ford's overheat with the cheap alum ones.

 

Sorry for not responding earlier, last Thursday going home rom work only made it about 4 miles before temp gauge started to climb. I was able to pull over before temp light came on and popped the hood to check upper radiator hose, it was cold, all indications lead to a stuck thermostat, or a air pocket that I didn't get out when I replaced it a couple months ago. Didn't buy a cheap one from a-zone,Any way I removed it and I'm running without one currently, no over heating issues since removing. Leaning towards another thermostat and see what happens, may also check for exhaust gases in resvior. Any tips on checking the temp sensor? Going to feel really stupid if it was another bad stat!

 

You need a tstat or you will run too cool. Actually will throw a MIL if under 170 at some point. Puts more wear on engine. I did that with a motorcraft that stuck open in cool weather.

get a motorcraft tstat. Not infallible, the one that stuck open on me was new, but chinese are crap.

 

The one i replaced a month ago was a motorcraft, guess it could have gone bad