The turbo spins at about 100k+ rpms at full chat. It is also bathed in exhaust gasses while running. Exhaust gasses that hover around 1100 deg F at full boost. Definitely want to let the engine idle for a few minutes after towing a heavy load or driving hard. Puttering around town is no big deal, but if you have your foot in the throttle, you should consider a cooling down period.

Warming up is somewhat important, though just idling a diesel usually doesn't do much to warm it up. Gently driving until the fluids come up to operating temps is a better option.

My experience is based on towing a 26' enclosed trailer with a crew cab diesel dually trucks, one which had an exhaust gas temp gauge. I've seen 1300 deg F exhaust gasses on short bursts w/a modified fueling program. It was no problem to regularly run all day long at 1100 deg F (post turbo temp measurements -- true temp probably 100 deg F higher).

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Kirk
Las Vegas
2016 X5 40e Mineral White/Black Dakota Leather, ZLL, ZCW, ZDA, ZDB, ZPP, multi contour seats, rear side window shades, HK stereo
2011 E90M3, 6-speed manual