powerwashing the motor.

my engine bay is pretty dirtty and i was wonder how to go about cleaning it, ive heard i can just powerwash it and its fine but wont that mess up some electrical things in there? do i need to cover the alternator with a plastic bag or something? and i have a fuse box under there to, should i cover that up? please help me.

It doesnt hurt to cover fuse boxes or electrical stuff I noticed the newer engines are a little more weather resistant but water can still be forced into some areas. The fuse box isnt always the worst thing to powerwash I have troubles with water resting in the spark plug areas causing the engine to miss. I had starters freeze in the winter time too because I didnt blow it off with an air tool also cover your filter element if it is an open setup. If its an older engine I have different cleaning methods but I got to go to work so maybe later.