overheating with 4.0 91 XLT 4x4 exp

[emtech708]

I have a 91 exp XLT 4x4 with the 4.0L Now A 5 speed, I drove to the gas station noticed the temp gauge was a little warmer than I thought it should be, I watched the gauge for a minute or so and it cooled down. Should I be driveing until it is repaired and was would make the motor do that?
I have not replaced the thermstat. I gauge fluxs in normal range on the factory gauge. from the O in normal to the a in normal all with about 35 seconds. I have heat inside and the top rad hose is hot, I am not used to the 4.0 motor yet HELP please

 

[Eric P]

Sounds like you have a bad thermostat. mine has done that.

 

[emtech708]

thanks will replace it today

 

[Infragate]

Here is the first thing to look at, do you have coolant in that radiator? I had a guy come to me once with a similar problem, turns out there was no antifreeze in the radiator, bone dry. If so then yes, replace your thermostat, sounds it is time. Flush the system too, there is some great posts on this site that can help you properly perform maintenance on the cooling system.

 

[marragtop]

When you replace the T-stat, make sure you also get the O-ring gasket. Also, one bolt is a bit of a pita to get to. I've found it easiest to take the serpentine belt off so that the tensioner swings out of the way.