Washing your engine

Why should you clean the engine compartment? Rust prevention, early oil/fluid leak detection, early belt wear detection and cosmetics are among the prime reasons. (There is a rumor that certain series of German mid/rear engine cars have a factory designed engine oil leakage feature to assist in rust prevention for the non-galvanized rear quarter panels and trunk areas.)

To soften the grease and grunge collected on your engine compartment, start the engine, let it warm up for a few minutes and shut it off. The proper cleaning temperature of the engine is warm but not hot. If you can just hold your hand to the engine without burning it, then it is warm enough to clean. As the engine cools to proper temperature, use the time to cover the few openings on the motor that dislike ingesting water. The air intake/air filter, the distributor, the coil and the oil dipstick/breather are among the few sensitive areas.

Use plastic Baggies and rubber bands to cover the air intake/air filter(s) and the distributor/coil. Place a double layer of Baggies over the air intake and secure with a couple of rubber bands. Use a pair of two-gallon size Baggies to cover the distributor and plug wires around the distributor cap. This may be difficult to seal, but the idea is to prevent significant amounts of water possibly shorting out the distributor. If the cap is in good condition, it will be waterproof, so this is only a preventative measure. The coil is also waterproof, so Baggies are again a preventative measure. Check the tightness of the oil filler cap, the power steering filler cap, windshield washer fluid cap, oil dip stick, battery filler caps and all other engine compartment opening caps and secure baggies over them with rubber bands.

Now that your engine is warm and sealed, spray the entire engine/engine compartment with a quality, non-petroleum based degreaser. Try to start from the bottom and work up. This way you dont have the degreaser dropping on your face as you clean the underside areas. My two favorite citrus based engine cleaners are P21S Total Auto Wash and Wurth Citrus Degreaser. I find that either of these two citrus products will clean thoroughly and not harm the paint or finish of the aluminum components and are biodegradable. One note of caution, all degreasers will remove your nice coat of wax. If you get the engine cleaner on the waxed areas, plan on rewaxing. Allow the degreaser about 3-5 minutes to work and then use a 100% cotton towel or a SOFT brush to GENTLY agitate the heavily soiled areas. Respray and rebrush any areas that need additional cleaning. Once the entire engine/engine compartment has been cleaned, rinse thoroughly with water. There is a debate as to the optimum force of spray to rinse the degreaser. Some say a gentle spray is all that is necessary, while others advocate the use of a high-pressure spray. Use your common sense. The stronger the spray, the more likely you will get water in sensitive parts. If all areas are properly protected, you should have no problems with a stronger spray. If any areas need additional cleaning, repeat as necessary.