You can purchase engine cleaner from an auto shop or even in a lot of grocery stores these days. Use an engine cleaner like this which is a strong degreaser/solvent & emulsifier/surfactant and take it to a car wash, spay 'er down (Use only as labeled) let it set a while then use the high pressure sprayer to rinse it down. Also a lot of do it yourself car washes have an engine cleaner setting that will do the trick! A couple of notes: 1.) You'll want to let your engine cool before you attempt to clean it. Applying a cold substance to a hot engine could crack your block. Also spraying an engine cleaner on a hot engine could be hazardous to both your engine and yourself. 2.) If you have a carburetor you'll want to seal your intake so that you don't have water or cleaner going into your engine. If its fuel injected it'll probably be sealed and you won't have to worry about that. 3.) You may need to repeat the treatment several times if your engine hasn't been cleaned in a while or if it's particularly nasty. Also, there are places that will clean your engine for you if you don't want to mess with it yourself. They can be somewhat expensive but they'll do a good job (they use high pressure steam usually) and can be held accountable if anything goes wrong. Look up auto detailers in your area you'll find someone who does this. Good luck. Keep 'em sparkling!

Always clean only a small portion at a time. never use water on a new car engine. since everything is electronic, water will short the system. i have used 409 cleaner with a hugh success. i have plenty of old rags and a toothbrush handy. spray a small portion, let it soak about 20 seconds, and wipe clean with a cloth. yes, this is time consuming, but the final rewards are well worth it.