Keeping an engine clean does more than to enhance its appearance. Oil and fluid leaks will
be easy to spot. A clean engine will run cooler and is easier to repair and maintain.
Start your engine cleaning routine by putting a plastic bag over the engine air intake. You may also want to protect other parts from moisture, such as the distributor and electrical parts. Aluminum foil often works where it is not possible to use a plastic bag.
Washing the engine is different from washing the exterior of the car since the dirt and grease can be tougher to remove. Making it easier is the fact that since most of the engine compartment does not have a glossy finish, we don't have to worry about scratches. For that reason, it is ok to rinse using high water pressure. You can then go at it with liberal amounts of soap and water. Unlike the exterior, it is ok to use common dishwashing detergent, since its grease cutting abilities can make the job go faster. You should use a mitt or sponge other than the one used on the car body however. If you've been regularly cleaning your engine, then an application of soap and water should do the trick. If grease and grime still remain, more drastic steps may be required. Stronger cleaners or solvents will handle the problem areas. A 50-50 mixture of kerosene and water will make a good homebrew grease cutter. Some detailers report good results using liberal amounts of WD-40. Let it soak for a while, then rinse thoroughly with a hose or pressure washer. Simple Green is not recommended, as we've heard reports of problems with certain kinds of metals. If necessary, use a putty knife or paint brush, with its bristles cut short for stiffness, to loosen the tough areas. SOS pads also work well on metal surfaces. A toothbrush can be used to take care of detail areas. Dry using an assortment of hand towels.
Battery corrosion and the battery box can best be cleaned with a 50-50 mixture of water and baking soda. The towels or rags used to clean the battery should not be used on any other part of the car.
Dressings can be applied to plastic surfaces and electrical insulation for a clean, new look. We don't recommend that you attempt to clean a hot engine, since it is dangerous and some parts could be damaged. We also hesitate to recommend steam cleaning. It can do an impressive job on those engines that have years of grime on them, but the process is harsh and can destroy valuable decals.
For a nice final touch, wash and wax the underside of the hood. It'll set the engine off well and complete the job nicely.