Background: Lycoming IO-360 in the Mooney 201 Overhauled in 1996 by Mena Aircraft Engines in Mena, AK Right at 2000hrs Until this past weekend, a fully unremarkable service history, no issues with this engine. Flying back from the holiday, partner noticed the oil pressure drop into the yellow, and at the same time #3 cylinder being 100*F lower on EGT compared to the rest of the cylinders. He made the immediate decision to divert and had an uneventful landing. Upon landing it was noted that the engine oil was low (3 qts.) with no signs of oil leakage on the engine externals. A&P on field pulled the #3, and found the oil ring damaged and slight damage to the piston. Supposedly no damage to the cylinder. I have no pictures to verify. This A&P conversed several times with our home A&P, and they decided the best course of action is to replace the piston and rings, and then we will bring the plane home. So, assuming the engine runs fine and get home, should we overhaul now, or with careful monitoring fly it another 2-300hrs? As said above, until now this has been a good running problem free engine.