2000 F150 V6 4.2
Is there any where I can find a diagram on the water distribution system?

 

It is pulled from the bottom hose of the radiator thru the water pump into the motor and heater. It returns by the top radiator hose via the thermostat housing. It is hard to get any complete picture due to the complexity of the surroundings. Looking to the hoses on the motor, testing the cap, inspection of leaking areas is best. Sometimes a mirror and a strong flash light. In the end it may be an intake manifold gasket problem. Pressurizing testing can help pinpoint the leak. Most problems come down to a leak via the water pump, a faulty thermostat causing overheating, belts, clogs in the radiator and internal motor gasket problems.