Hey folks.. just doing a water pump seal and noticed behind the water pump a deeper hole with some sort of irregular shaped foil hole behind it. I'm chasing a problem with coolant in the oil, and what seems like an air leak. The foil is thin... and not circular, and appears to connect the water pump directly to the crank case. I'm assuming this is a problem! Can I just plug this hole? Its odd that it is not co-planar with the crankcase gasket. Circled it in the picture.