Diesel Generator Preventive Maintenance

Maintenance of Diesel Generator is very important to reduce the fuel consumption, improve the efficiency and protect the environment from carbon and smoke produced due to incomplete combustion. The use of  right Preventive Maintenance Procedure can help to reduce the work related incidents and improve the quality of  Diesel Generator Preventive Maintenance. Diesel Generator Preventive Maintenance frequency can be as follows

  • Bi-YearlyDiesel Generator Preventive maintinance
  • Yearly

Bi-Yearly Preventive Maintenance:

  • Check and report for any abnormal noise /vibration.
  • Inspect connection for any water leaks.
  • Open up the electrical panel and control panel, inspect for any blackening of contacts.
  • Inspect the entire installation for signs of damage or overheating.
  • Sign of lubrication oil leakage
  • Coolant level in radiator
  • Fan belt tension
  • Sign of leakage from the fuel supply system
  • Sign of corrosion on battery terminals
  • Check batteries and battery chargers for proper operation.
  • Check batteries for correct water levels and excessive corrosion.
  • Verify automatic start switch is in correct position.
  • Restriction in exhaust air flow path
  • Sign of water leakage from radiator and hose connections
  • Restriction in ventilation air flow path
  • Check air cleaner restriction indicator. Replace the filter if necessary.
  • Report for any abnormalities.
  • Start up the generator set and run it for not less than 30 minutes.
  • Take records of all meter readings and the color of smoke while generator set is running.
  • Record for any abnormal noise and vibration during testing.

When the engine was shut down, carry out the following actions:

  •  Perform visual checks on any leakage and tighten connections wherever required.
  • Check the water level in the radiator and top up if necessary.
  • Check the lubricating level and top up if necessary.


  • Visually check the power cable connections between generator sets & switchboard.
  • Take records of meter readings including start count, run hour, water temperature, oil pressure,
    voltage, frequency, etc.

Control systems

  • Gauge the time during different stages of transfer to and from city mains and generator.
  • Observe the speed stability of the prime mover.
  • Observe the voltage stability of the alternator.

Fuel tank and fuel transfer system.

  • Check for sign of leakage.
  • Drain water content from prefilter (water separator), if any.

Associated switchgear

  • Check for sign of overheating.
  • Check for sign of damage.

Exhaust flue

  • Check for sign of rusting
  • Check that the flue is securely fastened.
  • Check and re-tighten any loose bolts and nuts in proper sequence.
  • Measure and record major operational parameters, including current, voltage, etc.
  • Grease the vibration isolators if necessary.
  • Inform the person responsible for the operation of the equipment of any changes or adjustments.

Load Test Conditions

  • Carry out functional and on-load testing using building load for generator and auto-change over switch of Main Switch Board if allowed.
  • Check all wiring terminals for tightness and condition of electrical components to ensure functioning properly.
  • Submit report including recommendations for any improvement works.

Yearly preventive Maintenance:

  • Perform Monthly services.
  • Perform Quarterly services.
  • Check engine block heater operation.
  • Check silencer and exhaust components for signs of rust.
  • Clean and lubricate battery posts.
  • Replace the lubricating oil
  • Replace the lubricating oil filter
  • Replace the air filter if necessary
  • Replace the coolant if necessary