Select Page

Maintenance Instructions for Electric Diesel Generator Sets

May 25, 2023 | Technical Literature | 0 comments

There are several points about the maintenance of diesel generator sets

As follows:


  • Check oil water and fuel leaks Coolant heater works properly.


  • Check oil level Coolant level Condition of flexible hose and connectors Oil level in daily fuel tank Oil level in main fuel tank Daily fuel tank Float switch Fuel transfer pump Battery electrolyte level Water pump drain hole Leakage Electrical wiring Whether the switch control device of the generator is in the automatic position and whether the alarm mode of the switch is in the normal position.

Per month:

  • Check the Air intake system for leaks Exhaust system for leaks Radiator resistance drive belt Electrolyte specific gravity (for lead-acid batteries only) State of charge (for maintenance-free and nickel-chrome batteries) Check that the batteries are clean Dry or not Corrosion Abnormal battery charger and charging rate Engine vibration Is there any obstacle at the air inlet and outlet of the generator room Whether the transfer switch works normally under load conditions The output voltage frequency of the generator.
  • Drain Oil Water Separator Daily Fuel Tank.
  • Observe circuit breakers and fuses to perform workload tests.

every 6 months:

  • Check the coolant DCA concentration Drive belt tension Intake pipeline and connector Flexible exhaust pipe joint Exhaust isolation and fire protection device Exhaust insulation and fire protection device Check whether the wires of moving parts are worn or not Electrical alarm and safety devices are working Normal power switch, whether the wiring of the power distribution cabinet is normal, check the resistance of the air filter, if it exceeds the specification, replace the tightening degree of the mounting bolts and vibrating parts, the tightening degree of the battery terminals and whether there is corrosion.
  • Drain sediment from main tank.
  • Clean electrical panels, cabinets and terminal boxes Clean generator rotors and stators with compressed air.

Per year:

  • Adjust fan and fan wheel-mounted radiator and air intake channel Daily use, whether the vent hole and overflow pipe of the main fuel tank are obstructed Exhaust resistance The hanger and supporting winding of the exhaust system and the working condition of the electrical connector oil return pipeline.
  • Watch supercharger.
  • Measuring insulation resistance with a resistance meter.
  • Acoustic radiator exterior and louvers.
  • Change oil Oil filter Coolant filter Fuel filter Oil water separator.


Two years:

  • Check the shock absorbers.
  • Change the coolant and flush the cooling system air filter.
  • Observe the full load test according to the power indicated on the nameplate.

When carrying out each level of maintenance procedures, firstly carry out all the content specified in the previous level of maintenance, plus the content of this level of maintenance.

The following is a detailed description of maintenance and inspection

preventive maintenance

Due to the continuous operation of the engine, most maintenance work is preventive maintenance. Preventive maintenance work mainly includes the following parts:

  • Routine inspection.
  • Maintenance of lubrication system.
  • Cooling System Maintenance.
  • Fuel System Maintenance.
  • Maintenance and Inspection of Starting Battery.
  • Routine Engine Check.


Routine inspection

  • Exhaust system: When the generator set is running, check the exhaust system including exhaust manifold, muffler and smoke exhaust pipe. Check all connections, welds, gaskets and seams for leaks and make sure the exhaust pipe is not overheating the surrounding area. Find any leaks and fix them immediately.
  • Fuel system: When the generator set is running, check the fuel supply pipe return pipe, filter and pipe accessories for cracks or wear. At the same time, it must be ensured that the pipeline does not interfere with other parts, which may eventually lead to pipeline damage. If any leakage or interference is found, it must be repaired immediately or the direction of the pipeline should be adjusted.
  • DC electrical system: Check the starter battery terminals to ensure clean and tight connections. Loose or corroded connections create internal resistance, making starting difficult.
  • Engine: The fluid level, oil pressure and coolant temperature must be checked regularly. The vast majority of engine failures have early symptoms. During the inspection, it is found that the engine has changed in performance, sound or appearance. This is often a signal that the equipment needs maintenance or repair. Special attention needs to be paid to: Difficult ignition, vibration, excessive smoke exhaust, power drop and increase in fuel consumption.

Maintenance of lubrication system

  • When the engine is stopped, check the engine oil level regularly according to the maintenance schedule shown in Figure 1. In order to accurately read the oil dipstick reading, wait about 10 minutes after the engine stops, so that the upper part of the engine oil flows back to the crankcase to ensure the accuracy of the liquid level reading. Strictly follow the grade and viscosity of the API engine oil recommended by the engine manufacturer, and make sure to add the same quality and brand of engine oil when adding engine oil.

Cooling System Maintenance

  • With the engine off, periodically check the engine coolant level as described in the Maintenance Schedule above. After the engine has cooled, remove the radiator cap and, if necessary, add coolant to 3/4 inch below the radiator cap. Frequently running engines require a certain proportion of water, antifreeze and additives in the coolant. It is best to use the coolant recommended by the engine manufacturer.
  • Check the outer part of the water tank for blockage, use a soft brush or soft cloth to remove foreign matter, and be careful not to damage the pipeline. If possible, use low-pressure compressed air or water jets to clean the tank in the opposite direction to the air flow. Verify that the coolant heater is operating properly by checking that hot coolant can drain from the outlet hose.

Fuel System Maintenance

  • Fuel oil stored for a long time tends to deteriorate, so regular maintenance operations such as start-up, operation, and testing every year can ensure that the fuel oil can be used before it deteriorates. In addition to other fuel system maintenance recommended by the engine manufacturer, the fuel filter must be replaced periodically as shown in Figure 1. Condensed water and other deposits in the fuel tank must also be drained and removed regularly.
  • Air boost lines should be checked daily for leaks, cracks, or loose connections. Tighten the clamps if necessary. Also, check the air cooler for foreign objects blocking the lines, and check for cracks or other damage.
    Engine intake components should be inspected at the time intervals shown in Figure 1. The cleaning and replacement frequency of the air filter is mainly determined by the operating environment of the generator set. Usually the air filter includes an air filter element, which can be cleaned and reused if it is not damaged.

Maintenance and Inspection of Starting Battery

  • Battery Testing: Simply checking the terminal voltage of batteries does not reveal their cranking ability. As the battery changes over time, its internal resistance will increase, and its termination voltage must be accurately measured under load. Cummins Power Gensets equipped with PowerCommand controllers automatically perform this test each time they are started. Other gensets require a manually operated battery tester to verify the condition of the starter battery.
  • Battery cleaning: Whenever you find dirt on the battery surface, wipe it with a damp cloth to keep the battery clean. If corrosion has occurred at the terminals, remove the battery cable and clean the terminals with a mixture of baking soda and water (1/4 pound of baking soda to 1 quart of water). Be careful not to get the mixture into the battery for cleaning. Rinse the battery with clean water after use. Apply anti-corrosion oil to the terminal after replacing the connecting wire.
  • Check the specific gravity: Use a hydrometer to check the specific gravity of the battery electrolyte. The specific gravity of the fully charged battery electrolyte is about 1.260. If the specific gravity is lower than 1.215, the battery should be charged.

Routine Engine Check

  • The application requirement that the standby generator set must run from cold start to full load within seconds is a huge challenge for the engine components. Regular starting and running of the generator set can ensure the lubrication of engine parts, prevent the oxidation of electrical contacts, and consume fuel to avoid its long-term storage and deterioration. It is an important measure to ensure the reliable start of the generator set. The generator set should be started at least once a month, and the load should not be lower than 1/3 of the nominal power and the duration should be more than 30 minutes. Due to the accumulation of underburned fuel in the exhaust system, the dead time should be kept as short as possible. In the case that it is inconvenient to test the actual load, the test can be carried out through the load box. Also, it must be ensured that the load box can provide a load not lower than 1/3 of the nominal power of the generator set. Through such start-up operation, the generator set can be Performance and service life are fully guaranteed.

Final conclusion:

Preventive maintenance of diesel generator sets plays an important role in increasing reliability, reducing maintenance and reducing long-term costs. Following and implementing general generator set maintenance procedures as well as manufacturer-recommended application-specific maintenance operations will ensure your backup power system starts and runs reliably when you need it most.

Finally, thank you for your patience in watching, I hope it can help you.

WhatsApp Online logo

Sales Team

Marine Service - SeaMacWhatApp-Icon

Automotive Service - DuraMacWhatApp-Icon

Industrial Service - ConeMacWhatApp-Icon

Generator Service - SinoGenWhatApp-Icon

Pump Service - PumpMacWhatApp-Icon

Parts Service - PartMacWhatApp-Icon

Sales Manager - Mrs. Wendy Fu

Sales Director - Mr. Jasper Lee       WhatApp-Icon

Shipping Service

Contact EMAC Now!

Subscribe To Our Newsletter

Subscribe To Our Newsletter

Subscribe to get the latest updates from

You have Successfully Subscribed!

Pin It on Pinterest