hydraulic oil in crankcase

[Ric27]

I have a early 90's md 1600 Yanmar. a squalling sound suddenly developed upon starting. checked oil, crank case full to top with hydraulic fluid. Please, any ideas as were to start look for the cause and solution.

 

[Roadworthy]

If the shaft seal on your hydraulic pump develops a leak the usual result is an overfilled crankcase. You may be able to replace the seal, have the pump rebuilt in a hydraulic shop, or replace the pump. The squeal may be the sick pump complaining or it may be something else entirely.