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I've used simple green and sprayed down a warm engine. Not hot, but slightly warm. I then let it sit for 5 or 10 minutes and hose it off. You could go as far as scrubbing everything down, but I usually just let it air dry and call it a day.
I use gunk engine brite with some water and a good scrub-down. Then i proceed to blow out any possible water from the spark plug valleys. I would say that if you are careful not to get alot of water on the top part of the engne you should be fine.
I only wash my powerstroke down I have never done the engine on the wife's exped but the truck get pretty damned dirty although this summer doing plugs I should probably give it a good scrub down