'97 F150 froze up?
After getting the oil changed in my 1997 Ford F-150 4.6L with 150K miles at a local quick lube, I made one stop and my truck wouldn't start. I could hear the starter engage the flywheel, but couldn't turn it over at all. Oil was clean and full. I bench tested the starter and it tests good. I put a breaker bar on the crankcase nut and I could barely move it. Oil level was about 2 quarts low before oil change. Any ideas what may have happened here, or what to try to break it free? Thanks