> Not been under yet, but would you assume that someone didn't replace that
> washer on the drain plug like they were supposed to? Would this lead to
> some leakage?

Yup. If the filter seal was leaking there'd be a *lot* of oil due to the
pressure.

To be fair, I often don't replace the seal on the sump plug. But then my
old wrecks usually have far more significant leaks from other places, so a
sump plug leak is insignificant :-(

Al.