SP33DYV said:
Philip Foglar said:
With any turbo engine I would allow it to idle a bit before shutting off, but most important is to do a "cool off" run as you are nearing your destination - nothing better than off throttle running under compression or just light throttle. The turbo is then working far less and is able to cool off far easier than even idling - reason being, when the car is now sitting idling there is then no airflow through the engine bay and the electric fan only comes on for the sake of coolant and engine temperature - so no point idling the engine if you have just been giving it horns!
I always drive slowly for the last couple of kilometers and then just let the car idle for about 30 seconds.
This is exactly what I would do, and can only do good even if the engine and turbo has some other clever cooling strategy after shutting off. My Isuzu (tractor) has an electric pump that you can hear pumping oil through the turbo for a few minutes after the engine has been shut down, but we still always let the engine idle for roughly a minute or so when stopping - and it's no big deal. In the time it takes to idle you are anyway busy gather your cell phone and whatever else you took with you, so 30 seconds for that matter is even easier.
The two things that is happening when you switch off is that the turbo is hot and is still spinning at fairly high speeds, so this is what you want to try and defeat with the cooling off and idling, to assist any of the built in turbo protection and cooling systems that the car has.
I still firmly believe that turbo life is in most cases directly related to how it has been cared for from day one and everyday!