1. Daily Inspection (Before Use / During Operation Intervals)

1. Check engine oil level

   Pull out the dipstick, wipe it clean, reinsert it fully, then check whether the oil level is between the “MAX” and “MIN” marks. Add qualified engine oil of the specified grade if insufficient. Do not mix different brands of engine oil.
2. Check coolant level

   Open the coolant filler cap (only when the engine is cool to avoid scalding). Verify that the coolant level reaches 3–5 cm below the filler neck. Replenish with coolant of the same type if low; avoid using tap water to prevent scaling and corrosion.
3. Inspect the fuel system

   Check whether there is sufficient fuel in the tank. Inspect fuel lines and connectors for leaks and tighten loose joints. Check the fuel filter for clogging or seepage; clean or replace it if abnormal.
4. Check the electrical system

   Ensure battery terminals are tight and free of oxidation; clean any oxides on terminals. Inspect wiring of the generator and starter for integrity, and check cables for damage or aging. Verify that dashboard indicators and gauges function normally.
5. Inspect appearance and fasteners

   Check the engine block and cylinder head for oil, water or air leaks. Inspect bolts and nuts (especially cylinder head bolts and connecting rod bolts) for looseness and retighten as needed. Check the tension of fan belts and drive belts; adjust if too loose or tight, and replace cracked or aged belts immediately.

2. Regular Maintenance (By Operating Hours / Cycles)

(1) Maintenance Every 50 Hours

1. Replace the oil filter. Remove the old filter, clean the mounting surface, apply a thin layer of oil on the new filter seal, then tighten to the specified torque to prevent leakage.

2. Inspect the air filter. Remove the filter element and clean dust with compressed air from inside out. Replace the element if damaged or severely clogged to ensure smooth air intake and reduce engine wear.

3. Check the cooling system. Clean dust and debris on the radiator surface to maintain cooling efficiency. Test the coolant’s freezing point and pH value; replace if unsatisfactory.

4. Inspect the lubrication system. Check engine oil cleanliness. Change the oil if it is dark, emulsified or contaminated. Verify proper operation of the oil pressure sensor and oil pump.

(2) Maintenance Every 200 Hours

1. Replace the fuel filter (primary and secondary). Remove sediment in fuel lines to ensure clean fuel supply and avoid wear on injectors and cylinders.

2. Inspect the fuel injection system. Check injector atomization; clean or replace injectors with poor atomization or dripping. Adjust fuel injection pump pressure to specifications.

3. Check and adjust valve clearance to standard values to prevent power loss, abnormal noise and increased fuel consumption.

4. Inspect the exhaust system. Check the exhaust pipe and muffler for damage or leaks. Remove carbon deposits to ensure unobstructed exhaust.

(3) Maintenance Every 500 Hours

1. Change the engine oil (drain while warm for thoroughness). Clean carbon deposits in the oil pan, install a new oil filter, then fill with specified engine oil.

2. Replace coolant. Flush the cooling system, remove scale and impurities, refill with new coolant and bleed air to avoid air locks.

3. Inspect clearance of connecting rod bearings and main bearings. Replace bearings if clearance exceeds limits to prevent abnormal noise and engine damage.

4. Conduct a comprehensive inspection. Check the cylinder block and head for cracks, inspect piston and piston ring wear, and examine the crankshaft and camshaft condition. Repair or replace worn parts as needed.

3. Maintenance Under Special Environments

1. High-temperature environment

   Increase coolant inspection frequency, shorten oil change intervals, and keep the radiator and fan clean to improve heat dissipation.
2. Low-temperature environment

   Use low-viscosity oil and antifreeze coolant. Preheat the engine before starting to avoid cold-start damage. Drain coolant during long-term shutdown in extreme cold to prevent freezing and cracking.
3. Dusty environment

   Shorten air filter inspection and replacement cycles; install a protective cover. Clean dust from the engine regularly to prevent internal abrasion.

4. Maintenance Precautions

1. Perform all maintenance when the engine is cool to avoid scalding and splashing of hot oil or coolant.

2. Use special tools and follow the engine manual strictly; do not operate improperly to avoid component damage.

3. Use only genuine parts and recommended lubricants, filters and coolers.

4. Keep the engine clean of oil and debris after maintenance for easier fault detection.

5. Keep detailed maintenance records including date, work items and replaced parts for continuous condition tracking.