Basically, ypu would not be able to start the engine, or if the engine was running, it would most likely stop. So filling to the level you discovered with a fully operational engine is rare. However, small
leaks can still allow the lubricating oil to be contaminated. So regular
inspection as suggested above is prudent.
Diesel is a good lubricant in itself. So major damage is not the norm in a short term situation. But long term, seriouse damage can occur. It is actually the cam surfaces that tend to get the biggest hiding. These are highly polished hardend
steel surfaces that normally have no bearing shells or rollers to take the wear. Diluted lubricant will not protect those surfaces for long.
A majorly over full crankcase such as you encountered will most likely blow
seals and you would have excessive oil
leaks from everywhere. And if it did start, the build up of lubricant in the upper
head area would quickly overcome the suction vent and you would most likely end up with a runaway. A litle scary when that happens. Hydraulicing the engine would not really be possible as the dilution would have to get high enough to flood the cylinders and fluid would have come out places like the dipstick and filler by then I am sure.