If your car breaks down at the side of the road it will certainly be an inconvenience and will delay your journey, but unlikely to be life threatening. If however your car breaks down whilst it is still moving the consequences could be entirely different, especially if you are travelling at high speed on a motorway, requiring you to react correctly and decisively to ensure your car is brought safely to a stop without causing an accident.
Most modern cars now come with power assisted steering and brakes, so if the engine fails it is very likely that these systems will be affected too. Therefore you will need to be prepared to use extra force to turn the steering wheel and place extra force on the brake pedal to bring the car safely to stop.
Most engines are now governed by an electronic control system that have a limp home mode if they detect a fault, and this could mean your speed is suddenly limited to under 30mph, even mini steam engine if you are travelling at a much higher speed. If you suddenly experience a loss of power switch on your left hand indicator lights and use gaps in the traffic to safely pull over to the side of the road.
If you detect an unusual burning or petrol smell, or see signs of fire pull over immediately and get all of the vehicle occupants out of the car and to a safe place as soon as possible. If the fire is inside the engine compartment do not open that bonnet, because the sudden rush of air will cause the fire to flare and burn even harder. Stay well back and call the fire brigade to handle it.
The first signs of an overheating engine will be on the rising temperature gauge inside the cockpit, which if left unnoticed can lead to steam coming out from under the bonnet. As soon as you suspect the engine is overheating pull over, switch on your hazard car bulbs and stop the engine as soon as possible otherwise the engine could be seriously damaged.
Allow the engine plenty of time to cool before investigating further, especially if you are going to remove the engine coolant filler cap and top up the fluid level. The reason for this is that the coolant system is a closed system and so whilst still hot will release scalding hot steam.
Modern car engines are normally extremely reliable, however faults do occasionally occur, so it is important to know how to react safely and correctly if they do.