Make sure the engine is cool to warm, but not hot. Open the hood and remove any leaves and twigs from the hood jams and under the windshield wipers as this debris will become more difficult to remove when it’s wet. Next, cover the alternator, distributor, and battery if exposed with plastic grocery bags. Use tape if necessary to secure the plastic to the component but keep in mind, this is just a precautionary step to avoid soaking that particular area in the event of a direct hit from the hose.
Then spray all-purpose cleaner or degreaser on the engine and do not allow it to dry. Work the cleaner into the engine and the hood jams with the wheel brush or a designated wheel wash mitt. Before the cleaner dries, lightly rinse the engine with the least amount of water necessary to flush away the grease, so you’ll need to work quickly.
Dry the engine with a terry towel and compressed air, or a vac and blow machine. Engines have many hidden and hard to reach areas that trap water, so using air can help dislodge the water before starting your car.
When removing the plastic bags, fold those inwards to trap the water and to avoid spilling them back onto the dry components. Once completely dry, add your favorite water-based tire dressing to the plastic components for additional shine. Afterwards, lightly buff the area with a microfiber towel to avoid a sticky surface as heavy application of dressing will attract dust to the plastic.
Lastly, start your engine to make sure everything is working properly and to help the last bit of moisture evaporate. Cleaning your engine regularly can help you notice future leaks and potential problems down the road. Remember to check your local town and county rules for public wash regulations.