Oil Leak Under UV Light

This is a rather poor picture of the oil leak under UV light. Dye was added to the motor oil a couple hundred miles before this picture was taken. Our first thought was that the timing chain tensioner o-ring was leaking. It’s a fairly easy repair, so we replaced it and rechecked. Unfortunately, the leak continued, and the only other possible source of the oil leak was the timing cover/head/ block joint.