Cooldown time

[James Hewett]

In the past when I ran a Diesel with a turbo on it, there was always a Warning tag, "Allow the engine to idle 3 minutes before shut down" ( to allow cooler oil and turbo to cool) wih exhaust temps hot enough to boil oil. I can't find where the Duramax needs this! Is it needed? why? or why not? Is it writ'n anywhere?

[Peter J. Bierman]

Turbo centerhousing should not be so hot couse it's water cooled, but shutting down the engine shut down water and oilflow through the turbo aswell.
Most importand is to have turbo RPM down to idle before shutting down or you have it spin at 60.000 RPM or more without proper lubrication and cooling.
Needed or not, it would not hurt to let it idle a wile.

Peter