hydraulic oil in the engine
I once had hydraulic oil transfer to the engine via the pump shaft seal, resulting in an overfilled condition in the engine oil tank.
I contacted P&W (it was a JT3) and they informed me that there was nothing in the engine (i.e. rubber shaft seals) that was likely to be affected, and they advised me to drain and refill the engine three times, with a run between refills.....no problems were encountered after this proceedure.
The JT 3 was pretty agricultural, and I am not sure if modern engines would be so forgiving, best thing is to check MM and if problem not covered, call the manufacturer.