DIESEL ENGINES SHOULD BE REPAIRED WHEN THE FOLLOWING SYMPTOMS OCCUR, EXCEPT FOR SITUATIONS WHERE THE ENGINE CANNOT ROTATE DUE TO BURNING TILES, STICKING TO THE SHAFT, OR POUNDING THE CYLINDER.1. DIFFICULTY STARTING. DIESEL ENGINES ARE NOT EASY TO CATCH FIRE, FIRST CHECK IF THE CYLINDER PRESSURE IS SUFFICIENT. IF THE CYLINDER PRESSURE IS INSUFFICIENT, IT WILL CAUSE THE COMPRESSION TEMPERATURE TO DECREASE. WHEN THE COMPRESSION TEMPERATURE IS LOWER THAN THE SELF IGNITION TEMPERATURE OF DIESEL (350 ℃), THE FUEL INJECTED INTO THE CYLINDER WILL BE DIFFICULT TO IGNITE AND BURN. THE REASONS FOR INSUFFICIENT CYLINDER PRESSURE INCLUDE WEAR OF CYLINDER WALLS, PISTONS, AND PISTON RINGS, LOOSE VALVE CLOSURE, POOR SEALING OF CYLINDER GASKETS, AND INCREASED COMBUSTION CHAMBER VOLUME.2. INSUFFICIENT POWER, HIGH FUEL CONSUMPTION, AND EXHAUST SMOKE. THE MAIN REASON IS POOR CYLINDER SEALING, REDUCED COMPRESSION PRESSURE, INCREASED GAS LEAKAGE, INCOMPLETE FUEL COMBUSTION, RESULTING IN A DECREASE IN DIESEL ENGINE POWER, INCREASED PRESSURE IN THE CRANKCASE, OIL LEAKAGE, EXHAUST SMOKE, AND INCREASED FUEL CONSUMPTION.3. INCREASED OIL CONSUMPTION AND DECREASED PRESSURE. THE MAIN REASON FOR HIGH OIL CONSUMPTION IS THE WEAR OF PISTON RINGS AND RING GROOVES, INCREASED CLEARANCE, AND ENHANCED PUMPING EFFECT OF PISTON RINGS; AFTER THE WEAR OF THE OIL RING, THE ELASTICITY DECREASES, THE OIL SCRAPING EFFECT WEAKENS, AND THE AMOUNT OF OIL ENTERING THE COMBUSTION CHAMBER INCREASES, RESULTING IN BLUE SMOKE IN THE EXHAUST. THE REASON FOR THE DECREASE IN OIL PRESSURE IS MAINLY DUE TO THE WEAR OF THE CRANKSHAFT MAIN JOURNAL, CONNECTING ROD JOURNAL, AND BEARING SHELL, IN ADDITION TO THE LOW VISCOSITY OF THE OIL AND POOR OPERATION OF THE OIL PUMP. THE MATCHING CLEARANCE INCREASES, AND THE OIL FLOWS OUT FROM THE INCREASED CLEARANCE, RESULTING IN A DECREASE IN PRESSURE.4. EACH OPERATING UNIT PRODUCES ABNORMAL NOISE. THE MAIN REASON IS THAT AFTER THE WEAR OF THE OPERATING COMPONENTS OF THE CRANKSHAFT CONNECTING ROD MECHANISM, THE CLEARANCE BETWEEN THE MATING PARTS INCREASES, AND THE STRESSED COMPONENTS ARE SUBJECTED TO ADDITIONAL IMPACT UNDER ALTERNATING LOADS, RESULTING IN NOISE. CONTINUING TO USE IT MAY CAUSE SERIOUS ACCIDENTS.