My Son Just Rebuild His 3.9 Engine... Short Block, New Oil Pump ,heads And All. When We Cranked It We Still Had No Oil Pressure And Oil Is Leaking Under The Truck Instead Of Going Into The Engine. Could Someone Give Me Some Info On What To Do Or Look For To Correct This Problem? I Dont Want To Ruin This Engine , As It Is To Costly. Thanks, Sharon

where is the oil leaking from? whenever you build an engine pressurize the oil system before installing the engine. i use a drill to spin the pump. this oils all the bearings before break in start up. i'm not too familiar with the 3.9 but it might be missing an oil gallery plug.