1. Leaky oil pan gasket or loose drain plug (see «Engine oil pan - removal, gasket replacement and installation»).
2. The seal of the emergency oil pressure sensor is broken (see «Emergency oil pressure sensor - replacement»).
3. Leaky seal of the cylinder head cover (see «1.6i engine cylinder head cover gasket - replacement»).
4. Worn or damaged crankshaft seals (see «Front crankshaft oil seal - replacement» And «Rear crankshaft oil seal - replacement»).