The only recommendation I´ve seen is that they say advice a 1 minut cool down on idle if you have been pushing the engine hard or your over the nominal operating temps.
What kills diesels is mostly full throttle while the engine is cold. Just be careful with the throttle until you get to around 2/3´ds of operating temps. After that, you can mash the throttle all you want. Then take it easy the last 2 miles home.