When this happens, the engine will have insufficient oil supply to all friction surfaces due to the lack of oil. This leads to abnormal wear or scuffing of the surfaces.

After the diesel generator set shuts down, the circulation of cooling water in the cooling system stops, causing a sharp drop in heat dissipation capacity. Heated components lose cooling, which easily leads to overheating of parts such as the cylinder head, cylinder liner, and cylinder block. This overheating may result in cracks, or cause the piston to expand excessively and get stuck in the cylinder liner.

When a diesel generator set starts from cold, the oil has high viscosity and poor fluidity, which results in insufficient oil supply from the oil pump. The friction surfaces of the machine suffer from poor lubrication due to lack of oil, leading to severe wear. In extreme cases, faults such as cylinder scuffing and bearing burnout may occur.

Insufficient cooling water in the diesel generator set reduces its cooling effect, causing the diesel engine to overheat due to ineffective cooling. Excessively high temperatures of cooling water and oil can also lead to overheating of the diesel engine. At this time, key components of the diesel generator set—such as the cylinder head, cylinder liner, piston assembly, and valves—bear heavy heat loads. Their mechanical properties, such as strength and toughness, drop sharply, increasing component deformation and reducing the fitting clearance between parts. This accelerates component wear, and in severe cases, may even cause faults such as cracks and component jamming.