As your temperature gauge rises higher than normal, going closer to the red zone, you are given the first indicator that your engine is overheating. The second indication is the warning light your vehicle has to tell you the car is running hot. This light is typically found on the dashboard, and you may see steam rising from the bonnet. When any of these signs appear you need to stop driving the vehicle. To continue driving is asking for brutal and costly injury to the engine.
As soon as you get any indication that your engine is overheating you need to pull over and switch your engine off. Carrying on, even until you reach a service station or garage, could create a large amount of damage to the engine, especially the cylinder head, which is prone to warping under high temperatures and will be very expensive to replace.
When you get to the side of the street you will need to turn your hazard lights on to indicate you are experiencing an issue to the other drivers. If there is no fire you can lift the bonnet to give the engine a better source of air, thus decreasing the pressure. You do not want to touch the engine as you may be burned.
It can take a significant amount of time for the engine to cool down, so you should be prepared for a long wait. If the car overheats during the night hours make sure your sidelights are lit and that you turn the headlights on so you can see what you are doing around the engine.
After the engine has decreased in temperature the first thing to check is the coolant. This is usually the first fluid to be low when your car overheats. By adding water to the radiator you are able to give it fluid. The water should not be too cold as it can crack the container the fluid is held in. Water is not the typical fluid to use, but in an emergency it works fine. The water will dilute the coolant called antifreeze. You will need to have the system flushed by a mechanic before winter to avoid freezing the coolant.
The filler cap on the coolant can still be extremely hot even after the engine has cooled down. Underneath the cap is pressure which will cause steam to rise when it is released. This could burn your hand. It is imperative to make sure the radiator is cool to the touch, as well as to use a rag to cover your hand when you open the filler cap.
Reaching out at arms length to fill the container will help stop you from being hit with hot coolant. You will want to stop and check the levels of the reservoir to ensure you are not over filling it. There is a maximum and minimum line on the container. You will need to check that the temperature gauge is back to normal levels before driving again.
Remember that whilst your car is safe to drive again, there is an underlying problem that caused the overheating, so avoid a long journey and take it to a suitable garage to be checked out as soon as possible. However, if the engine overheats again, shortly after you have set off, you need to pull over and call a roadside recovery service as you have a serious problem that will require the services of a garage to fix it.