i have a 1989 cherokee with 4.0,4x4,automatic. i have changed the entire cooling system from closed to open system with all aluminum 3 row radiator, no thermostat, new overflow bottle, running 1 gallon of 50/50 coolant and the rest water, also took engine fan off and have dual electric fans on switches and running fans constantly. while driving on flat land temp runs between 180-200 but as soon as i hit incline it starts climbing and gets up to 240 and starts boiling and i have to stop and let cool off, this is a off road vehicle so dont drive it on the road....does anyone has any suggestions because i dont know what could cause this?

 

make sure you your thermostat is good. if so run a temp lower all it will do is make your heat not work as well . also take your thermostat out this will let you see if you might have a small crack in the head not impossible. Or maybe your trans cooler or heater coil is clogged they still take away some heat 240 is not that high when looking for overheating . a fan shroud may seem like a small thing but it make a difference when talking about 40 degrees above normal temp

 

^^ Reading comprehension?

I usually don't knock people, it's not in my nature. But re-read his post, lmao.

He doesn't have a thermostat to begin with.

He removed the mechanical fan, and has dual electrics. So theres nothing to shroud.



Outside of that,

What CFM are the fans rated at? Also, what kind of condition is the rest of the cooling system in, i.e. coolant block passages, water pump etc?

 

With the correct mix of coolant/water AND a properly functioning/correct rad cap, coolant shouldn't boil at 240F.