some people might disagree ... but i would avoid engine wash

today's cars have so many electrical connections subject to corrosion if the engine is washed too often carelessly. corrosion is usually the culprit for intermittent electrical/engine problems and can be very difficult to troubleshoot, resulting to costly repairs, e.g., replacing parts unnecessarily. if you ever need to have the engine washed, locate/identify critical connections and make sure the mechanic provides some cover as protection from water.