what would cause the overheating of a Jeep Liberty 2006 3.7L that has had the radiator & thermostat & water pump.there's no leaks and the heater is blowing cold air

There is probably an air pocket in the system that has reached the water pump. If there's no water in the pump it will not be able to circulate the water in the cooling system. You may want to fill the system from the top return hose to fill the system, or you may also losen the fluid connections to the heater core to get the air pockets out... and fill the system as high as possible.

I will give that a shot & update you upon completion. Thank you.

I would flush, the hole system. some one before you, or ealeryer, my have had a leaking problem, and instead of fixing it wright, put bars leak in it. that stuff will clouged every little orifice it can, including your heater core. one time i had to take it to my local self car wash place, and remove the heater hoses from the fire wall, and blow out the core from both inlet and out let, do it several times to be sure and the hoses if you can, you'll see rusty colored sludge come out, and keep blowing it with the hot high pressor water, until you see clear water....hope this helps

I have a 2002 jeep liberty that the drain plug in the radiator keeps poping out while driving it