Two types of lubrication oil leakages :

1. Crankcase oil leakages to outside of crankcase – Controlled of zero leakages by the mechanical seal

    on both ends of the crankshaft.

2. Oil leakages within the crankcase – lubricating oil for main bearings & crankpin bearings – controlled     by maintaining within limits the maker’s recommended clearances of the main & crankpin bearings