I assumed my engine cover was to keep excessive water from soaking the electronics that are located on top of the engine. Mine came loose because I lost a rubber insert that holds the plastic cover to the engine, but I reformed a new one using silicone gasket compound.

Pete

'01 Rodeo Sport, 5 Speed Softie, Indy 4X rocker bars, OME 912's, Rancho 9000X's, Superwinch hubs, custom tube bumper with Warn 9000i , Flowmaster 50, TeraLow t-case gears, ARB front & rear lockers, TrXus MT's, Sway bar disconnects