i have an 89 cherokee pioneer, its the 4.0 6 cylinder. its not over heating but when it reaches about 190-200 degrees the water is presserized in the coolent resivor and leaks out through the cap in massive amounts. could anyone give me an idea of what could be the problem. i have filled it correctly with the correct amount, but after driving for 20 min or so. this happens when i turn it off. any informatino would be helpfull. thanks

 

Either the cap is bad or the bottle is hooped. Try replacing the cap and see what happens. It could also be that the system is getting over pressurized by a head gasket problem but over heating would usually come with that. The pressure bottle (closed system) type of cooling system in the xj's usually have more than their share of problems due to the plastic bottle so if the cap doesn't do the trick, check into swapping to a newer rad and getting rid of the closed system for good.

 

cool thanks! i will look into it.