I just bought this xj not to long ago and took out wheeling for the first time last weekend I was on one of the trails and my tempter got alittle to hot past 210 but not in the red yet but when it did that my radiator cap popped open spewing coolant everywhere. Is that normal? I checked for signs of headgasket being blown but seemed fine so I let cool filled it back full of coolant and the next was able to drive home 50 miles with the engine not overheating at all. Anyone know why my radiator cap would pop up like that?

 

Broken, poorly affixed cap?.. I just replaced mine and it sorted out my mysterious in-traffic overheating and regular coolant loss. It's only $6..

 

I'll lookinto gettin a new one