94 Toyota, 4 WD truck, 3VZE. On the drivers side, just above the oil pan there is something round that is bolted into the block. There is a water line runing into it. It would appear I have an oil leak here. I tightened the bolt but that did not seem to help.

Thanks.

 

That's likely the oil cooler....it has a gasket/o-ring inside that goes bad and can be replaced.