Answer
If engine already not slowed down, the slow down, inform bridge, check navigational constraints.
If you can stop the engine, stop it asap.
Close fuel oil supply, switch off Aux blower, Open skylight doors, keep engine room blowers running, evacuate the engine room. Lub oil pumps keep running and if possible, increase the flow/pressure.
Do not come in for 30 minutes.
Enter inside - Prepare FF equipment, Stop LO pumps, feel/temperature checks by gun - then open the CC door - CC inspection for hotspots - standard procedure.
Simultaneously - EO check OMD sensors, calibrate sensors, check alarms levels/limits, check any electrical malfunction, cables. Checks as per maker manual - different types of alarms.
Wrong calibration of the sensors: Interchange with other unit or renew with spare (Life of the sensor is mentioned in the manual)
Vent pipe of the crankcase - going to mist box - is choked. Need to inspect the breather pipe.
Box back and sail - Alarm is coming ag ain - now what?
Alarm limits - can change:
Normal working value = 0.9 mg/l
Alarm value = 1.3 - 2.4 mg/l (Adjustable) - Class allows upto 2.5 mg/l LEL = 50 mg/l - M67 IACS.