i just signedup to the fourm but have been getting info from here for a while. i know overheating has been covered but my problem seems diffrent. fan clutch is solid,changed thermostat and flushed system. jumpered electric fan to battery, fan ran for an hour no problem. jeep overheats temp goes from normal 200ish to overheating quickly. after awhile temp drop to around 215. while the jeep temp was climbing i pulled over popped the hood electric fan was barely turning. water pump is 2yrs old. also replaced the relay
thanks

 

You can replace the entire cooling system for ~ $200 and a couple of hours time. That's a lot less expensive than a new engine.

 

halfway there now. bugs me when i cant find a problem