I don't douse an engine with a garden hose, can cause too many problems. Instead, I use a squirt bottle of Simple Green (or similar) and another squirt bottle of plain water. Spray the worst areas with the Simple Green and let sit a bit, now scrub those areas with a scrub brush or old toothbrush in the tight places. Now squirt with plain water, it doesn't take that much water to rinse the dirt and Simple Green off. Don't forget to wipe down hoses and wires with a shop towel and clean them all up as well. When you are done making the engine look good, give the engine bay some of this attention too. God is in the details, they say. ;) You can really make and old engine bay look new, if you put some time into it and without making the car hate you later. Lots of water does nothing for you (but causes the car to not run), it just rolls off the oil and grease.
Charles