I have a 95 xj with the 4.0. I have a new radiator, dual electric fans, hood louvers, and a new tstat. Still when I'm cruising in a trail or like now I'm in glamis cruising in second gear my jeep still over heats. No leaks anywhere, no white smoke or anything. It just gets up super hot and I cannot figure out what else to do. I live in San diego so my cool an mix is like 60/40 water/antifreeze. I don't wanna just throw parts at it if they don't need to be replaced, but don't know what else to do. Oh and my heater core was biased by the previous owner

 

Have you done any sort of testing for a bad head/head gasket?

 

yea sounds like an air bubble or a bad head gasket

 

Haven't done any pressure testing, but it's never low on coolant either. When it gets super hot the overflow fills up and some might come out of there, but otherwise it's never low

 

How is your water pump? Have you flushed the rest of the system?

 

Sounds to me like you may have restricted flow somewhere

 

I would replace the water pump just a precaution, they're not too expensive.

 

What temperatures are you seeing?

What brand and temp t-stat did you install? Also more info on electric fans, it is hard to find an electric fan setup that performs as well as the factory mechanical fan.

 

Is it boiling/bubbling in the overflow bottle?

 

Nothing pull more air than factory fan set up.

 

I don't let it get higher than 220 (that's when my second fan kicks in) I had the cooling system flushed about 9 months ago. Fans are 11" Spall pullers. When I drove up Oldsmobile here in glamis is the only time it boiled and came out the overflow

 

It was an autozone special and the temp was 195

 

220° is not overheating. That's a little warm, but even with my 100% brand new cooling system in a newly rebuilt motor, I occasionally reach 220° in certain circumstances. If it's not constantly running that hot, I'm not sure there's cause for concern.

I'm not entirely sure what that means.

If you're saying you towed an Oldsmobile somewhere with your Jeep, you may just have gotten the transmission hot. On the other hand, if you have a leaking head gasket, that can allow exhaust gas to escape into the cooling system and cause a boil-over of the coolant bottle. Sometimes a leak like that will be more pronounced when towing or driving the motor hard. Exhaust gas escaping into your coolant will naturally heat it up and make the Jeep run hotter.

You can buy a combustion leak tester for about $50 that will tell you if you have exhaust gas in your coolant. Some mechanics or shops have them and may be willing to test it for you for free or for a small charge. If it tests positive for exhaust gas, you know you have a head issue, probably just a blown head gasket.

 

Definitely check that water pump. There was a guy on here a while back whose water pump was so bad (the fins on the impeller were rusted away) that it wouldn't circulate the coolant properly.

 

Haha sorry, Oldsmobile is a hill in glamis. Big sand hill that people race and drive up. I try to not let it get over 220, but it does. It goes into the red and I shut it down before it maxes out.