When the fluid in the expansion tank is at the COLD mark, start the engine.
If the overload warning continues, there is one more thing you can try. You can add coolant directly to the radiator, but be sure the cooling system is cool before you do so.
Warning. Steam and boiling liquids can severely burn you. They are pressurized and if you turn the radiator cap they can come out with a lot of pressure. Do not open the radiator cap until the system has cooled down.
1. You can remove the radiator high pressure cap when the cooling system, including the radiator cap, the radiator hose is cool. Turn the radiator cap slowly counterclockwise to the first mark. Do not push the radiator cap down. If you hear a hiss, wait until it stops.
2. Then turn the cover further, but at the same time press it. Remove the cover.
3. Fill the radiator with 50/50 DEX-COOL coolant mixture to the base of the filler neck.
4. Next, fill the reservoir up to the COLD mark.
5. Close the tank cap, but do not close the radiator.
6. Start the engine, wait until the upper radiator hose warms up. Watch the motor fan.
7. This time, the coolant level inside the radiator may decrease. If the level has dropped, add coolant through the filler neck until the level rises to the bottom of the filler neck.
8. Then screw the radiator cap in place. At any time, if liquid leaks from under the cap during this procedure, reopen and close the radiator. Make sure the arrows on the radiator cap are positioned as shown in the picture.