1993 Ford Ranger Thermostat Problem?

[geon]

Hey there, I have a 1993 Ford Ranger, and I just got the radiator repaired.
After a while of driving, I noticed on the Engine Temperature bar on the dashboard go pretty close to the right, near the H. (Hot)
But then after about 5 minutes it goes back down to Normal...then it starts to heat up again. And then goes back down closer to Normal after another 5 minutes or so. And it repeats this over and over.

Does anyone know what the problem might be?
I think it may have to deal with the Thermostat, or the Temperature Gauge or something.

Thanks,

 

[boggs1227]

replace the stat and make sure you burp the system for air really good .

 

[Blacksheep Josh]

Also make sure you test the thermostat before putting it in. I recently read a tip for doing so. Put it in a pot of water, and bring it up to a boil, see if it opens. If it does, remove it from heat, and see if it closes. That way you can test for defects before you even install it.

 

[best X]

that just happened to my explorer but the mechanic said it was because of a leaky head gasket and the termostat so

 

[Four0Sport]

sounds like an air pocket in your system.. let it run w/out the radiator cap on, when the air pocket passes through youll notice your coolant drop in your radiator, start filling slowly till it gets back up, put the cap back on. you just burped a baby, somewhat.

 

[knoxville]

first make sure you have enough coolant in the system check i would just replace the thermostats cause its a 5 doller part and it doesn't take to long to do and flush and refill with new and if that isn't it check the temperature sending unit the gauge seems to be working fine if it is moving.


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Mr Gasket