Idle racing and Temp goes up & down

[Nonoy]

I did a search and I wanted confirmation. Could this be a bad thermostat? I noticed after a long drive (650 miles) with stop and go traffic, my idle was racing and the thermo gauge goes up if I am in a constant 65 miles/hour and down when in a slow traffic. How hard is it to change the thermostat? Help

 

[Magicfan25]

Really I would think that would be the other way for a bad thermostat. At 65mph I would think just the air flow would keep it cool and when in slow traffic it would get warmer.. But I'm wrong alot....

Changing a thermostat isnt bad. I did two of them this summer (not on Explorers).
Follow the top hose from the radiator to the top of the engine block. Thats where the thermostat is.

You will lose a gallon or so of coolant, so either drain it first, or pull off somewhere its ok for it to leak (is not REALLY ok anywhere..and deadly to animals.but anyways..)
Remove the hose at the top of the block. Thermostat will pull right out. Make sure you put the new one in right side up (usually a pic on the box to be extra sure). I used some Carquest Blue gasket maker on both sides of the gasket for the thermostat housing (make sure to buy the new gasket).
Not sure on the burping process for new cars because of the overflow containers so hopefully someone will chime in.

 

[dogfriend]

burping thread: Dead Link Removed

On the thermostat, make sure not to put the new one in backwards. The spring side goes toward engine. I know this from experience

 

[Nonoy]

I replaced the thermostat. Problem solved! A 30 minutes job! It takes 15 miles/gal of gas with that kind of problem wowwww