Dont run straight coolant, it doesn't exchange heat as good as water. Run 50/50, thats what supposed be in it when it works fine so don't try and compensate for a other problem. As for it running hot do you have some way of checking the temp other then the gauge? When im at work scan tool data, or what the computer is getting from sensors, actually varies quiet a bit from what the dash indicates. Check your drive belt for tension, check and make sure you don't have an air pocket some where. Try taking a hose off thats in a high location like above the water pump in the front of the engine and top off the cooling system until coolant runs out and stick the hose on real quick, that helps bleed trapped air out. Also when ever you drain the cooling system when you start the car up and your adding coolant be sure to run the heater at the same time that way the flow control valve is open and you don't trap air in the heater core. Maybe check for a restricted radiator, also try another T-Stat, I've gotten bad ones right out of the package. BTW don't run it with out the T-Stat because you'll have to much water flow and it will eventually over heat if you run it long enough because the water moves to fast to exchange heat when it reachs the radiator...or the Jeep will run really cold in some cases, like going on the highway. The impeller could be corroded or defective some how on the water pump too so again check for coolant flow. Does it just over heat while sitting still or always runs hot moving or not? Check the fan clutch too, when those go out they slip a lot at idle and the Jeep will run hot until you begin to move. Let me know what helps!
