1997 Explorer Sport 4.0 SOHC 71,000 miles

We have had this truck since new. My son is now driving it. Last night he mentioned that the "engine" light has been coming on/going off for the last five days (kids) and that last night he noticed the engine temp gauge going from cold to hot fairly quickly. I checked and sure enough, after a 20 mile drive the gauge was reading just barely below the high side of the normal range. Coolant was flushed/refilled at about 52,000 miles. Level is normal. No leaking. My initial thought was to replace the thermostat and maybe the sending unit, but after reading some of the posts I saw reference to a TSB for temp gauge. Did this also apply to the 1997s? Also, it just didn't FEEL like an engine that was overheating. Wondering if I should just replace the thermostat and sender anyway, or is there an easy way to check for the gauge problem referenced in the TSB?

Thanks

 

Check the radiator cap as well as watch for circulation with the cap off,, Make sure the truck is cold before you take the cap off and then start the truck to see if there is any movment in the fluid, this might take a minn for the thermostate to open but it sounds like the water pump is bad, once the truck is a normal temp and the thermostate opens you should see the fluid flowing and it should get sucked down when reving the mottor, go with the simplel thing first and change the thermostate but watch the waterpump,

 

I'm curious why you would suggest the water pump. I guess I am used to a failed water pump actually leaking. If the shaft is turning, why would it not be pumping? Or are you suggesting buildup of deposits or some opening that is plugged in the pump itself?

 

I have had expereance where the water pump fins stoped turning and it caused a head gasket failure because I thought it was the therm. Just making a sugestion Mine water pump was not leaking but it still was no good

 

As it turns out, I was lucky. Turned out to only be the thermostat.
All seems to be well now.

I will keep the water pump in mind for the future, though, should I run into an overheating problem on this truck again.