Sudden drop of stern tube oil level
Kobelco Compact Seal CX-500, oil-lubricated stern tube seals (aft and forward)
Possible cause
Leak from aft or forward seal
What to do
Manufacturer's manual, p. 31Find leak; with double security type close spare-seal valves and use ring #3S
See the assembly on the 3D model
Other Kobelco Compact Seal CX-500 faults
Stern tube oil above 60 °CBearing damage, cooler or thermometer faultEmulsified oil or seawater in drainDamaged No.1/No.2 rings or trapped foreign matterFresh water in drainLeak from aft peak tankForward seal tank level changesNo.4 or No.5 ring damage
From the manufacturer's manual “EM-35 KOBELCO COMPACT SEAL-STERNTUBE SEALING”. Check against the original on board before work.