1. Drive to the edge of the road, stop the car, switch the lever to the "P" position - for an automatic transmission, or turn on idle speed - for a manual transmission; apply the handbrake. If the air conditioner is running, turn it off.
2. If coolant leaks or steam comes out of the radiator or coolant expansion tank, turn off the engine; open the hood and wait until the steam evaporates. If neither steam nor liquid comes out, do not turn off the engine, but check: does the cooling system fan work. If not, then turn off the ignition.
3. Additional control.
Check the water pump V-belt: is it loose or cracked?
Visual inspection: radiator, radiator hoses and underside of the vehicle for leaks. It is acceptable if water drips from the air conditioner after use. When the engine is running, be careful not to let your hands or clothing get close to the moving fan and V-belt.
4. If the V-belt is cracked or if coolant leaks, turn off the engine immediately. Contact your Toyota dealer for necessary repairs.
5. If the V-belt is OK and no coolant leakage is detected, check the coolant expansion tank. If it is empty, add water to the tank while the engine is running. Fill it approximately halfway.
Warning! Never attempt to remove the radiator cap if the engine and radiator are hot. Severe injuries can be caused by boiling liquid and steam escaping under pressure.
6. After the engine has cooled to normal temperature, check the fluid level in the tank again. If necessary, fill the tank halfway. A significant loss of coolant means that there are leaks in the cooling system. The cooling system should be checked at a Toyota workshop as soon as possible.
(The material was borrowed from the website MitsubishiMan.ru)