The heat gauge in your car is an important warning tool before you do real damage to your car. A gauge in the red zone means your engine is cooking, which could cause extensive damage throughout the car. However, if you catch it just before you hit that red line, you still have a chance to cool off the car and prevent serious damage from occurring.
If the air conditioner on the car is on, the cooling system in the engine has to work harder. On very hot days, this means the engine doesn't get cooled properly. Immediately shut off the air conditioner when the needle approaches the red zone. Turn the heater on full. This provides a vent for the heat in the engine. Open the windows so you don't get too uncomfortable in the car with the heater on.
It is imperative you pull over as soon as it is safe to do so when a vehicle is in danger of overheating. Find a shoulder with a pull-off lane or pull into the nearest available parking space on the street and turn off your vehicle.
Once you've safely pulled over, you may open the hood of the car. Don't do this if your car's gauge has moved into the red zone. Don't open the car hood if you see any signs of steam or smoke under the hood. When you open the hood, wear gloves or wrap your hand in something to protect it while you lift the hood. Keep your head and face turned away from the engine compartment when you open it in case steam has built up under the hood.
Wait until the temperature of the car has dropped into the "cool" range on the temperature gauge. Remove the radiator cap to check the amount of coolant in the system. Keep your face far away from the opening when you take off the cap, and wear a glove or wrap your hand in a towel or shirt to protect it from any steam that might escape. If the coolant is low, refill it before you drive again.
