2000 TJ Temperature Spikes

[sinatranate]

I am having a new problem that my temperature spikes, seemingly at random. High speed and high gears, low speed and low gears, and at idle. Temp will shoot to 260, and stay there. Then, also seemingly at random, it will drop to 225, and either stay there, spike back up after a minute, or drop to normal 165. I have a new IAC valve from AAP, and have thoroughly cleaned my throttle body. I am thinking it might be my t-stat, but wanted to get some other ideas before taking to a mechanic.


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[sandplasma]

There could be an air bubble in the cooling system. One way to get rid of air is to remove the radiator cap when the jeep is cold and leaving it off. Then turn the car on and wait to see if you see bubbles rising up. After a while, close it up and drive around to see if its gone. Remember not to reopen the radiator cap after the car is hot.

 

[sinatranate]

I emptied out my radiator, did a flush. Ran water through it, then refilled with full strength AF. I think it unclogged my heater core and something else in my system, b/c now it idles around 210 with no fluctuations, and the A/C blows cold again...


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[sandplasma]

Great to hear!