I just changed thermostat, water pump about 4 yrs ago. System is full of air and cannot figure out how to bleed it, no heat. Is there a way to bleed the system or is there a potential failure (without leaking or squealing) of the water pump?

 

Rex,
I see that you have a 2000 4.0. I have a 3.0 and the bleed valve on mine is located to the right of the coolant expansion tank it is on the end of the small hose. I am not sure about your 4.0