Over heating

low on antifreeze ? fan working ?

All fluids are good. Fan works also. Chewing over the idea of the thermostat?

Okay lets go over the thermostat and its function first. If it is stuck in the closed position it would cause an over heating problem as water is not circulating through the cooling system. So lets check if it is opening without removing it from the system first. I will start by explaining how it works in the system. When an engine is cold the thermostat is closed until the temperature of the coolant in the cooling system reaches normal operating temperature between 160 and 195 degrees depending on the vehicle and year. Once the coolant reaches this temperature the thermostat opens permitting circulation of coolant in the system. The thermostat also has cross ports to restrict the flow of coolant to permit it to cool in the radiator by way of the radiator fan prior to reentering the coolant system. At normal operating temperature the fan will kick on to keep the fluid cool. ( Make sure the ac is turned off during these tests). To check if a thermostat is opening is simply done by squeezing the radiator hose when the engine is cold . The hose will be cold and pliable easy to squeeze with little resistance. as the engine warms up and the thermostat opens the radiator will stiffen and become warm indicating circulation of coolant and the fan will turn on if electrical. If mechanical meaning turning at all times it will incorporate a clutch meaning the fan will spin faster than when cold. If the hose gets stiff and warm the thermostat is opening and fluid is circulating. If the fan is turning and the hose does not get warm and stiff the thermostat my be stuck closed. When replacing the thermostat coolant will be lost and when replacing it the system must be permitted to purge while filling the system. This means it is a closed system and air gets trapped while filling and must be permitted to escape. Don't just fill it cap it and drive it. Allow it to recede as air escapes and ad more coolant until it no longer recedes. This will take a few minutes between receding and filling several times until it no longer recedes. If the fan is mechanical ( clutch fan ) the clutch may no longer be working and a new one is needed. This can be checked by rotating the fan by hand when the engine is off and cold and noting a stiffer resistance when the engine is warmed up and also turned off. If you find everything is working as described , thermostat is opening and fan is working properly. the next thing to check is a blown head gasket. Signs of this could be white smoke from the tail pipe and loss of coolant or milky oil meaning the coolant is mixing in the combustion chamber or with the oil. To test if coolant is entering the combustion chamber a chemical block test can be done . This is a clear large syringe with a rubber seat at one open end to insert into the radiator or reservoir fill hole and a rubber bulb squeeze at the end of the tube. The tube is filled with a blue liquid chemical that will turn green if exhaust fumes are entering the coolant system indicating a blown head gasket when the rubber bulb is squeezed and released drawing in air from the radiator or reservoir fill hole .

Changed the thermostat. Friend was determined to do it.. but the van is still over heating. Cooling fans only turn on if the AC is on, and only runs for less than a min and the temp gauge does not drop. Fans spin freely when I do it by hand.