We could go over this and bicker, I clean all my motors, and have no problems. Many fleet companies that used ford vans and trucks, 4.6/5.4, like Uhaul and enterprise, all clean under the hoods, mostly with pressure washers. My company uses many test vehicles from ford and its required at every 5000 miles to be done with all the checks and fluid samples. Not one problem, and we use pressure on them.
Not telling anyone to use pressure, but a garden hose will not hurt in my opinion and has not in any of my experiences....
I am really not looking to fight with anyone over this guys, just explaining my reasons.