You should not use a power washer on a modern engine. The force of the water jet can inject water into you electrical wires and connectors. As far as the engine temp is concerned. Engine off and cold is the safest way (of course if its winter you donâ??t want the water to freeze so donâ??t wash it in the winter). A good rule is to use or hands as a guide. If you wouldnâ??t want your hands to be hit with the water jet, then donâ??t hit the engine bay with it.
As far as cleaners. Petroleum based cleaners like Gunk do a good job on warm engines but they smell and are rotten for the ground water. Use the less toxic stuff like simple green or orange blast. If your bay was really dirty, you should find the source of the leak and fix it.
As far as using silicon based products under the hood. They are great for your 60â??s-70â??s classic or you hot rod, but donâ??t use them on cars with O2. The silicon will out gas when the temp gets hot. The gas will be sucked into the air box and shorten the O2 sensors life.
jeff
