XJ Goes Above 210 When First Started

[Kris_R]

Hey guys, I had a quick question. Does anyone's XJ go above 210 when you first start it? Every time I run it from a cold start, the temp gauge goes a little above 210 (enough that I can see the black background between the needle and the 210 marker.) after that it drops just below 210 and stays there. It doesn't matter if I'm driving or idling, it won't go back above 210. I don't remember my previous XJ or my TJ doing this. Is it normal?

[Brasscatz]

Hard to say what's normal for these, they all seem to do everything a little different. My thought is to replace your thermostat. It may be sticking a little at first, then once it opens you're good.

Sent from my Samsung Galaxy S4 because my microwave couldn't do it

[Kris_R]

That was my first thought as well. It supposedly has a new thermostat in it, but I know how many are bad out of the box.

[denverd1]

give the stat the ole boiling water test. if it doesn't open, toss it in the trash

[prerunner1982]

Mine does this on occasion as well, but I know the coolant isn't that warm since i typically have the heater going and the air is anything but warm. I believe it to be an air bubble, that is trapped near the temp sensor until it gets flowing good. I do need to check the coolant level though.

[nickyg]

Replace it with a "fail safe" one so when it fails it'll stay in the open position. So your rig will run extra cool when it gives out instead of extra hot.

[4.3LXJ]

That is not abnormal, many stats do that. Your stat opens after warming up and there is probably some coolant that is warmer from the rear of the engine that has been stagnant that needs to pass. If you want to smooth it out a little, drill a very small hole in the top of the stat. It will bleed air better and pass a little coolant, but not enough to affect anything. The only time I wouldn't do that is in areas with prolonged extremely cold winters. I do it on my engines