How Should I Clean The Engine Compartment?
[AT] Try a mixture of Simple Green diluted with water sprayed on and left to soak for 20 minutes. Then use some hot water and have a high pressure nozzle with a fan shape spray to wash it off. Then use some compressed air and blow off all the connectors and wiring and dry off the engine compartment as much as you can before you start it. Take the car out for a drive to heat up the engine and let it do the rest.
[MW] For polishing the alternator, I used Blue Magic Liquid Metal Polish. Got it at Pep Boys. It says its safe and nonabrasive, works on chrome, aluminum, copper, brass, silver, stainless steel. It removes oxidation and tarnish. I suspect any metal polish would work! I’m tell’n ya it made a big difference in the engine appearance!
[GM] Simple Green or Finish Line Citrus Degreaser. Full strength or dilute as necessary. Spray on cool engine, agitate with 2" paint brush, hose off.
[GL] I have not tried steam cleaning, but I have cleaned the front and rear compartments with great success using water and Simple Green. I cleaned it with the engine cold and used a wrag to wipe all the components. Gently spray the sand away with water. Be cautious on not using too much water pressure.
By the way, wrap up the fuse boxes and the alternator with plastic bags to prevent possible water damage. When you are done, go for a very long drive to evaporate the water. It’ll probably take a few days for all the water to evaporate away. Afterwards, your friends will swear that one could practically eat from your engine.
[GM – 99/3/22]
Repeat for other side:
You can use solvents (I like Gunk) for tough deposits, and you will want to wrap an aftermarket exposed air filter with plastic, then secure it with a tie wrap or duct tape before washing. Wax the painted surfaces (bulkhead) and use a protectant like Black Again or 3M vinyl and rubber spray on the hoses and plastic boxes when finished. Keeping your engine clean like this should mean you never have to resort to more powerful cleaning methods.