AFTER USING DIESEL ENGINE OIL FOR A PERIOD OF TIME, DUE TO THE INFILTRATION OF EXTERNAL IMPURITIES AND OXIDATION REACTIONS, THE OIL GRADUALLY LOSES ITS LUBRICATING PERFORMANCE AND MUST BE REPLACED IN A TIMELY MANNER (THE OIL CHANGE CYCLE IS SPECIFIED IN THE DIESEL ENGINE MANUAL). IN THE FOLLOWING SITUATIONS, DUE TO POOR ENGINE OPERATING CONDITIONS, THE OIL CHANGE CYCLE MUST BE SHORTENED.VEHICLES DRIVING ON ROADS WITH HIGH LEVELS OF DUST AND SAND, AND DIESEL ENGINES OPERATING IN ENVIRONMENTS WITH HIGH LEVELS OF DUST (SUCH AS THRESHING, MILLING, GRINDING, AND FEED CRUSHING), HAVE MORE DUST ENTERING THE CYLINDER THROUGH THE AIR FILTER, EXACERBATING THE WEAR OF THE DIESEL ENGINE. THESE IMPURITIES ALSO ENTER THE OIL PAN AND CONTAMINATE THE ENGINE OIL.2. DIESEL ENGINES THAT FREQUENTLY OPERATE IN HUMID ENVIRONMENTS (SUCH AS PUMPING WATER) ARE PRONE TO CONDENSATION OF WATER DROPLETS IN THE CRANKCASE, WHICH CAN SEEP INTO THE ENGINE OIL AND CAUSE IT TO EMULSIFY AND DETERIORATE.3. DIESEL ENGINES OFTEN OPERATE AT LOW THROTTLE AND LIGHT LOAD, AND DIESEL CANNOT BE FULLY ATOMIZED AND BURNED, WHICH CAN EASILY FLOW FROM THE CYLINDER WALL INTO THE OIL PAN AND DILUTE THE ENGINE OIL.4. DIESEL ENGINES OPERATING IN COLD REGIONS ARE PRONE TO DIESEL CONDENSATION AND MIXING INTO THE ENGINE OIL, REDUCING THE LUBRICATION EFFECT OF THE ENGINE OIL.5. DIESEL ENGINES THAT FREQUENTLY OPERATE IN COASTAL AREAS HAVE HIGH CONCENTRATIONS OF WATER VAPOR AND SALT IN THE AIR, WHICH ACCELERATES THE CORROSION OF DIESEL ENGINE PARTS AND MAKES THE ENGINE OIL PRONE TO DETERIORATION.DIESEL ENGINES THAT FREQUENTLY OPERATE AT FULL OR OVERLOAD CONDITIONS (SUCH AS CRUSHING ROCKS) ARE PRONE TO OXIDATION AND DETERIORATION OF THE ENGINE OIL DUE TO HIGH ENGINE TEMPERATURE AND CARBON DEPOSITS.DURING THE RUNNING IN PERIOD OF A NEW OR OVERHAULED DIESEL ENGINE, IF THERE IS AN INCREASE IN MECHANICAL IMPURITIES IN THE ENGINE OIL DUE TO FRICTION AND WEAR, IT IS ALSO NECESSARY TO CHANGE THE ENGINE OIL EARLY.BEFORE THE DETERIORATION OR MAJOR OVERHAUL OF THE TECHNICAL CONDITION OF THE DIESEL ENGINE, DUE TO THE EXCESSIVE CLEARANCE BETWEEN THE RELEVANT PARTS IN THE CYLINDER, THE COMBUSTION OF THE DIESEL ENGINE IS POOR, CARBON DEPOSITS INCREASE, AND HIGH-TEMPERATURE EXHAUST GAS EASILY ENTERS THE CRANKCASE, LEADING TO OXIDATION AND DETERIORATION OF THE ENGINE OIL.IN ADDITION, WHEN DIESEL OR COOLING WATER SEEPS INTO THE OIL PAN OF A DIESEL ENGINE, OR WHEN THERE IS A BURNT TILE OR SHAFT ACCIDENT, THE ENGINE OIL MUST BE REPLACED IN A TIMELY MANNER AND THE LUBRICATING OIL CIRCUIT MUST BE CLEANED.