Sorry to differ with you Volvospeed, but I would NOT recommend steam cleaning, unless your engine is CAKED with grease and dirt, etc.

Steam is far more invasive than water, so if you were afraid of water doing damage, steam is much more likely to do worse damage. Yeah, you'll be able to blame someone else, but, to me, that is not an advantage. Steam lifts all the warning stickers from whatever they are attached. If you have a weak point in paint, steam will exploit that weakness.

Just buy some of that spray-on foamy stuff. Maybe even two cans. Spray it on and let it sit for a while.

When you spray it off, use some common sense. For areas that contain electrical, or ignition, connections, don't spray using the sharp stream.

When you are done, since it will probably be a warm day, leave the hood open for a couple of hours and let everything dry out.