Originally Posted by ultimatesailer
There was no sign of problems with the head gasket. It was only replaced once but the oil was changed many time so the volume would not build up and blow a seal. Without a crack in the block or head how could the water get in the oil? Tkx
Unfortunately, you've probably covered the other reasons already.
As a slight possibility, your water pump may only leak when it's spinning, so your test may not have been good.