I recently purchased a non running 1992 Ford F-series truck w/7.3 diesel engine, 90,000 miles and the drivers side valve cover was off and about five of the eight push rods were moderately bent. I have not checked under the other valve cover yet! Can anyone recommend the steps to take to find out why this happened? The Government owned the truck and they just turned it in for a replacement truck, it sat for a year and they don't remember what happened to it. Should I pull the head/s first? Why would so many push rods bend? water in the fuel? I think a leaking head gskt may cause one or two push rods to bend but, five? I would pull the heads but it may be better to leave them on to diagnose the problem? any help with this would be appreciated. Thanks!