1994 jeep cherokee overheating while ideling

rjmidbon

New member
My 1994 jeep cherokee 4.0L inline 6 at idle for ten minutes reaches 260F I have a new radiator, water pump, thermostat, heater core valve, and new valve cover Gasket, I have a new heater core and oil pump but have not put them in yet. I do not have oil in my radiator fluid nor do I have water on my oil dip stick so I concluded that it is not a head Gasket, but the little electric fan does not stay on when the vehicle reaches this temp nor does the radiator feel hot I would think that the radiator would feel hot since water boils at 212F. I just have water circulating through the system now for I wanted to make sure I had no leaks in the system, did not want to waste money on Antifreeze/Coolant until I checked everything that is new first, will remove bottom hose when I find out what is causing this excessive heat in the engine. Anyone with feed back on this would be greatly appreciated
 

U don't have to have water in the oil to have a bad head gasket try putting the fan on a toggle switch so u can run it when u want maybe change out the temp sen. To see if the temp gauge is right or not at 260 it should be boiling
 
It is your head gasket. I recently did mine and it was bad. But no over heating though. Or your clutch fan is shot ..
 
If and when you pull the cylinder head off, you might as well take it to a machine shop and get the head checked for cracks and if there's no crack, have it resurfaced before you put it back together.
 

I would check to make sure your clutch fan in engaging and the electric one should kick on with either a/c on or when temp gets around 217. If it's not the fan could be bad or the temp sensor could be bad. You could tap into the electric fan w/ a relay and add a switch to override. should work in tandem with the factory set-up. Another option is to upgrade your current electric to the newer 97+ (maybe 96+) fan, better blade design, higher CFM. Direct drop in - might have to cut the old connector off and tie into the new one to make them match.
Also is your radiator cap good? Might want to pick up a higher pressure rating - this will help raise the boiling point of the coolant
 
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