Oil would help keep it from rusting if anything... Lol iv moved countless motors. Anything from little 4 bangers to a big 1950s caddy v8. Place it uprigt, and strap er good. Shouldnt move and shouldnt leak if kept upright. They sit upright under the hood and dont leak(usually unless its got something wrong with it) and if it does say you will wash the entire truck not just the bed LOL never know