Originally Posted by JohnCrabtree
Would you have to worry about getting water on electronics/in your cylinders if you just used a garden hose rather than power washing? I've always been hesitant to wash my engine bay because of all the horror stories I've heard about having to buy a brand new PCM or having a misfire because some got past your spark plug
Do not power wash your engine! Garden hose should be fine, a plus if you can hook it up to warm or hot water. When I do mine I cover anything sketchy with aluminum foil (don't cover your battery with foil though, just disconnect it and remove it) such as the pcm, distributor cap, and alternator, also the belt if you left it in. Everything else should be more or less water resistant. Oh yeah and cover your throttle body if you take the intake off of it.
Basically apply whatever degreasing solvent you choose, let it sit, and rinse. It helps to have a soft thin brush to help get in all the nooks too. Repeat as needed. When it's done you can use a leaf blower or air compressor to blow the excess water out of all those nooks.
Then I personally like to apply some sort of engine shine/coating so it'll be easier to clean the next time.
Also don't run it while you're rinsing/cleaning it and make sure your manifold isn't blazing hot when you hose it off or you'll crack it.