This is actually quite normal and nothing to be concerned about. If the engine temperature is high enough, the computer will continue to run the cooling fan even though the ignition has been turned off. This helps keep the temperature from spiking when the vehicle stops and is turned off.

Even though this only really lowers the temperature of the coolant in the radiator (not in the actual engine) it also helps to maintain a constant, safe temperature if you restart the car soon after shutting it down.

That said, the fan should only continue running for a couple of minutes at most after you’ve turned the car off. Any longer and you might have a problem with the circuits that power and control the electric fan.

A common cause of overheating can be a failed head gasket which allows the coolant to be consumed by the engine. When this happens, soon there’s not enough coolant remaining to cool the engine and the car overheats.

But it may not be as serious as that. You could simply have a stuck thermostat. This is the component that prevents coolant flowing around the engine when it’s first started, forcing the engine to warm up faster. Then, as the engine gets warmer, the thermostat starts to open to allow the coolant to flow through the engine and do its job, maintaining the correct running temperature in the process.

Other possible causes for overheating include incorrect ignition timing, a slipping fan belt, non-functioning cooling fans, a collapsed radiator hose, blocked radiator, a worn water pump and many others. A good mechanic should be able to make a diagnosis and tackle the problem from there.

You could have an engine problem that is causing the vehicle to lose power. The cause of this could literally be a thousand different things. An electronic scan of the vehicle might shed some light on the root cause of the problem, and most mechanics would carry out such a scan before doing anything else.

If the engine is not at fault, you might find the problem can be traced to a transmission that is not shifting gear properly or is slipping, or perhaps even something as simple as a dragging brake or poorly adjusted park-brake. But before you hit the workshop, you can check simple things like the condition of the engine’s air filter to make sure there’s no obvious cause. If your car is a turbocharged model, check the plastic trunking that carries the boost from the turbo to the engine’s intake. This trunking can split or fall off, leading to a loss of boost pressure and, therefore, performance.