Originally Posted by 427 fordman
After the truck sits overnight, pull the drain plug carefully and see if water comes out before oil. How fast does your water level drop? The knock could be an injector, but if it has had a lot of water in it you could have also wiped a bearing or more out. Headgasket failure on a stock truck is not very common, but anything can happen.
If have to wonder if the stress from water and running the truck out of oil could have spun a bearing. How long will a truck run off the hpop reservoir oil