I use a 50/50 mix of Super Clean/water. Super Clean is available at WM, and works great. I think it works better than Simple Green, which has a funky smell to me.
Anyway, I use a spray bottle set on "stream" to hit all the hard to reach areas, than a quick once-over the rest of the engine with the spray bottle set so that it will fan out the spray. Let it sit for just a few minutes then use hose water to wash down the entire thing being a little careful around the electronic/electrical stuff. I've done this literally hundreds of times with no problems.
I agree with what Scot said: If it needs to stay dry, Ford designed it to stay dry. I would add one more thing: Ford did NOT design things to stay dry when subjected to water from a pressure washer. I don't ever use THAT on the engine compartment.