Martlor13

Hey guys. I have a 99 xj. For about a month now I was mysteriously losing a slight amount of coolant. Maybe about a quarter of a cup every 50 miles. I thought it might be a cracked head. I went to rent a coolant pressure tester. Hooked it up and saw some leaking around the upper radiator hose where it connects to the radiator. Pressurize again and see more leaks. I tight it might be the lower radiator hose but I don't think so. If I had a leaky radiator would I over heat? I don't now but am just curious. We're in a wind storm now so I'll do some more checking in the morning.

jt_aleshire

Shouldn't over heat until it gets so low that the water isn't cooling enough before it is cycled back threw the system so answer is it will eventually run hot when it gets low enough

Remus Redbone

Not likely to overheat running down the highway, but if you are rolling around slow, or under load, you might see some heat. A cooling system that won't hold pressure is compromised. The boiling point of water is 212F / 100C at sea level atmospheric pressure. A sealed cooling system operates at higher pressure & allows water to stay liquid to a higher temp. In your compromised system you're going to start turning water into steam Not far above 212F. Steam doesn't cool very well. I wouldn't do any trailer pulling until repaired.