Ignore the slightly oily areas, all engines occasionally "spray" some lubricant.
However, you should pay attention to obvious oil stains and leaks under a parked car.
The engine should be cleaned using a steam generator or engine cleaning agent.
After a test drive of several kilometers, it will be possible to determine the location of the oil leak.
Possible leak locations
Crankshaft, distributor and intermediate shaft seals (for four-cylinder engine only) shafts. These places are hidden under the toothed belt cover.
Cylinder head cover gasket.
Cylinder head gasket.
Fuel pump base gasket.
Gasket on the ignition distributor.
Oil pressure indicator switch.
Oil filter gasket.
Gasket on oil filter holder (four cylinder engine only).
Oil pan gasket.
Rear crankshaft oil seal (oil leaks from the junction of the engine and gearbox).