We answer a question about letting a turbocharged engine and its oil cool down before cutting the ignition.
Is it necessary to let a turbo engine idle for a few minutes before I switch the ignition off?
Turbocharged engines do need to cool down before they are turned off. But in nearly all driving conditions, the engine does not reach temperatures that require a deliberate cooling-down period.
Switching off when the engine is very hot stops the circulation of oil. The layer of oil around the turbocharger bearings stop flowing and literally gets “burnt”. The black sludge that forms is not good for any engine.
In all other situations, even sustained high-speed driving on expressways in Singapore and Malaysia, there is inevitably a period of low-speed driving before parking the car or switching off the engine. That is sufficient for the engine oil to cool to a level that will not damage the turbocharger bearings.
Also, always ensure that you are using the recommended grade and viscosity of engine oil for your turbocharged car.
