Follow the manufacturer’s schedule
Service intervals depend on engine model, operating hours, calendar time, fuel, environment and application. Always use the operation and maintenance manuals for the installed set. The checks below are a practical framework, not a replacement for model-specific instructions or competent service work.
Weekly and pre-start inspection
- Look beneath and around the set for fuel, oil or coolant leaks.
- Check engine oil and coolant levels with the set safely stopped and cool.
- Confirm fuel level, tank valves and visible fuel-line condition.
- Inspect belts, hoses, wiring, guards, exhaust supports and ventilation openings.
- Check the control panel is in the correct automatic mode and no alarm is active.
- Confirm battery charger and coolant heater indications.
- Keep the enclosure, plant room, intake and discharge paths clean and unobstructed.
Exercise the generator under meaningful load
A brief unloaded run proves that the engine can start, but not that the complete system will carry the building. Follow the site regime for regular exercise and, where safe, test the automatic mains-failure sequence. Bring the engine to normal operating temperature and observe oil pressure, coolant temperature, voltage, frequency, charging and unusual noise or smoke.
Repeated light-load operation can encourage carbon build-up and wet stacking. Periodic load-bank testing applies a controlled electrical load and helps prove cooling, governing, alternator performance and output protection.
Engine oil and filters
Check oil level before operation and investigate any unexplained change. Replace engine oil and filters at the specified hour or calendar interval, whichever comes first. Use the grade and specification stated by the engine manufacturer. Record the quantity, product used, hours and date.
Cooling system
Inspect coolant level, concentration, hoses, clamps, radiator core, fan and belt condition. A blocked radiator or recirculation of hot discharge air can cause failure only when the generator reaches load. Coolant additives deteriorate with time; sample or replace coolant according to the engine schedule. Never remove a pressure cap from a hot system.
Diesel fuel and storage
Water, sediment and microbial contamination can block filters and damage injection equipment. Drain water traps where fitted, inspect tank condition and monitor stored fuel. Long-retention systems may need sampling, polishing or tank cleaning. Keep stock rotated and use fuel that meets the engine manufacturer’s current specification.
Starting batteries
Battery failure is one of the most common causes of a no-start event. Inspect terminals, cables, electrolyte where applicable and physical condition. Test standing voltage, charger output and starting performance with suitable equipment. Replace ageing or weak batteries as a complete matched set where the system uses multiple units.
Controller, protections and ATS
Review active and historic alarms, emergency stops, sensor operation and remote signalling. Test the automatic transfer switch in a controlled manner, including mains sensing, start signal, transfer delays, retransfer and cool-down. Inspect contactors or breakers and ensure interlocks prevent unsafe source connection.
Keep a useful maintenance record
Record dates, run hours, readings, faults, corrective work, fluids, filters, battery tests and load-bank results. Trends often reveal deterioration earlier than a single pass/fail inspection. Store current manuals, wiring drawings, spare filters, belts and approved fluids where the service team can find them.
When to call a generator engineer
Arrange competent support for repeated alarms, difficult starting, unstable voltage or frequency, excessive smoke, fluid consumption, overheating, fuel contamination, insulation concerns, protection trips, synchronising faults or any work involving live power and changeover equipment.