For cleaning the engine of car
Warm up the engine slightly
Move the car to an area where the soap and material cleaned off will not cause damage or enter a storm drain
Remove the negative terminal cable on the battery then the positive.
Cover any exposed electrical components with a plastic bag or plastic wrap.
Cover the breather or air intake and carburetor on older engines with heavy aluminum foil or plastic.
Brush any loose dirt or debris from the engine surfaces, either using a stiff bristle paint brush, or a plastic bristle cleaning brush
Mix a solution of "grease cutting" dish detergent and water, using about 2 cups detergent to one gallon water.
Brush your solution on the engine, working it into the dirtiest areas, wetting them thoroughly.
Get a garden hose.
Consult the vehicle's service manual and look up material that will be needed to clean the engine block and other metal parts
Remove plastic after rinsing engine and cleaning away residue of whatever chemical that you used to clean the metal compose.
Remove all the materials you used to cover electrical and fuel system components.