Open the oil filler cap and check the gasket for cracks or damage.
Check the tightness of the ventilation hoses on the cylinder block, valve cover, air filter or intake manifold.
Valve cover gasket.
Cylinder head gasket.
Installation location of the ignition distributor flange.
Oil filter gasket. A Oil pan drain bolt and gasket.
Connection between engine and gearbox (gasket on the flywheel or on the gearbox shaft).
Since in the presence of leaks, the oil spreads over a large surface of the engine, it is difficult to determine the location of the leak at first glance. When searching, it is recommended to work in the following sequence:
Wash the engine with special cleaners, which must be washed off with water after exposure to these cleaners. Before washing, cover the generator and fuse box with plastic wrap.
Apply talcum or chalk powder to engine joints and gaskets.
Note: In workshops, a special aerosol composition is used for this.
Check engine oil level and top up if necessary.
Take a test drive. Since the oil becomes more fluid when the engine heats up and flows out of the leaks faster, you need to drive about 30 km and at high speed.
Then examine the engine with a portable lamp, detect leaks and eliminate them.