What does everyone do as far as washing under the hood. Is it okay to spray directly onto the motor. Should the engine be running or not? What about the engine cleaner stuff at the car washes?

Hose it down every time vehicle is washed. (about every 6 weeks) Engine off. No problems. Don't know about engine cleaners. Never used any.

I just lite spray mine off with water about every 3 times I wash the truck, been doing it this way for about 25 years and never had a problem, as for the cleaners I never had to use them.

Be careful not to get your connectors wet, all the electronic stuff. Very first time I washed mine, water and mild soap, I got some electrical wet and truck spit and sputtered , scared me till I figured out what I had done, just had to unplug connectors and dry off.

Read the posts here for more info:

http://dieselplace.com/forum/showthread.php?t=16404&highlight=wash+engine

i use simplegreen on mine. works fine