running hot to overheating at idle

[smcdonaldaz]

There are also the "traditional" problems that would cover high-temps at cruising speed--dead or dying water pump, clogged cat, etc.

What's the expected life span of the cat and how can it be tested? I have 93 with 120k.

 

[ehall]

only way to diagnose is remove it and look through the ends for daylight

 

[cpolish24]

I was having the same problem with my jeep a few days ago. (It would get up to 235-240 on the Hwy. going 65mph and 68 outside.) It seemed to be a restriction of air flow through the rad. I replaced the fan clutch and Its been perfect ever since, never goes past 195 anymore! (And I ran it hard on the hwy. just to be sure it was fixed.) I also replaced my rad cap just for good measure, because if a cooling system can keep presure it will cause the system to overheat a little bit.

 

[smcdonaldaz]

I was having the same problem with my jeep a few days ago. (It would get up to 235-240 on the Hwy. going 65mph and 68 outside.) It seemed to be a restriction of air flow through the rad. I replaced the fan clutch and Its been perfect ever since, never goes past 195 anymore! (And I ran it hard on the hwy. just to be sure it was fixed.) I also replaced my rad cap just for good measure, because if a cooling system can keep presure it will cause the system to overheat a little bit.

Did you replace both at the same time? Everything I've read says that over heating at slow speeds indicates the fan clutch is bad and that the fan has no effect at speed. Did you put in the XJ or HD ZJ clutch?