About the truck in Sitka Alaska that had an entire gallon of water in the bottom of the crankcase oil pan. Tom and Ray think the water accumulated due to combustion blow-by gas condensing the water vapor. Their reasoning is that the many short trips where the engine didn’t fully warm up over the 10 year period and the oil hadn’t been changed could cause this. Maybe, but I can’t imagine an entire gallon of water accumulating. That is, unless the PCV valve wasn’t working. The PCV is supposed to vent the crankcase gasses, but if it was clogged up, the water vapor in the crankcase might never be vented, and that might be contributing to the cause. I think the truck owner should check the PCV valve to make sure it is working, and check the associated hoses and oil filler cap to make sure they are not leaking vacuum.
They got it wrong. I had Jeep 4cyl and a boat that did it. They were both were parked over the winter. It’s condensation. I don’t know how it happens to get this much water but it does. I all way’s changed the oil before I parked them for the winter. On the boat I started to leave the oil plug out over the winter. I sold the Jeep. It never seemed to hurt the motors.
Good comment @oldbodyman. Like you, I don’t think it has to do with running the engine. Almost all of the exhaust gas goes out the tailpipe, very little into the crankcase. He said he’d only driven the truck 500 miles. It doesn’t seem like that could produce an entire gallon of water in the crankcase.