I have pics of how clean I keep my engine in my webshots at the bottom of the page. I don't use engine cleaners or simple green. The engine cleaners will stink so bad for the next month you will be sorry you ever used them. Simple Green will etch aluminum if left on to long, I use the purple degreaser or something similar. You should cover the alt, and the power steering fluid cap as it has a small air hole. I find it's better to spray on a warm motor, NOT HOT!!!, let it sit for 15 min , then hose off with a high pressure hose, not a power washer!! Also try not to spray the hose directly at any connections. I then let the truck sit with the hood open all day to dry. Many have had problems starting a truck right after washing the engine, and it can be a real pain to take apart all your connections and dry them with a hair dryer. I like to do this on warm days, it dries faster. Then I use a product called Engine Detailer from AZ, it leaves a nice clean engine without bad odors. If you have any ?'s just PM me.
Kevin