So here is what is happening.I have a 96 jeep cherokee has 98,000 miles on it.When I start it up it's fine then I start to drive and the needle shoots all the way up.I turn my heat on and the needle starts going down slowly.when I go on the highway it also tends to not be all the way up.It seems to be going back n forth.Is it a bad gauge? I do know that I need a coolant temp sensor and a may need a thermostat.would there be any other issues to solve this? I opened the hood when the gauge was all the way up and the engine didn't seem that hot at all.please if anyone can respond to let me know that would be great.

 

its a bad temp sensor or you have a bad wire somewhere

 

Does aux cooling fan come on during this ?

 

Yes the fan comes on.i am going to replace the sensor and just go from there.

 

Good start. post back results .

 

I also just noticed in the overflow bottle it's empty.now I checked the radiator and there was a little bit around the top that I could see sitting there but how can I tell how much coolant I have?

 

had the same problem with mine for coolant, you might either be leaking coolant or you might have a blown head gasket