What is included in a generator 250-hour service?

A 250-hour generator service is a minor service that includes draining and replacing engine oil (typically 15W-40 CI-4/CK-4), replacing the engine oil filter, inspecting the air filter element, draining the fuel/water separator, checking coolant level and concentration, inspecting the radiator and hoses, checking fan belt tension, running a load bank test at 25%, 50%, 75% and 100% rated load, checking the exhaust for smoke and leaks, inspecting exhaust flex couplings, checking vibration isolation mounts, inspecting fuel lines and connections, checking the control panel, testing the emergency stop, checking earth connections, checking battery terminals, voltage and electrolyte, and inspecting the enclosure or canopy. It takes approximately 1 to 2 hours.

Why is load bank testing important for generators?

Load bank testing verifies that a generator can deliver its rated power output and identifies issues that only appear under load. Running at 25%, 50%, 75% and 100% rated load checks voltage stability, frequency regulation, cooling system performance and exhaust condition. Generators that run on light load for extended periods can suffer from wet stacking (unburnt fuel residue in the exhaust), which reduces performance and damages components. Regular load bank testing at each service interval prevents this and confirms the generator will perform when needed.

What oil goes in a generator engine?

Most diesel generator engines use 15W-40 engine oil meeting CI-4 or CK-4 specifications. Typical engine oil capacity ranges from 8 to 20 litres depending on generator size. Some manufacturers specify different grades for extreme cold or hot conditions. Always check the service manual for your specific make, model and operating environment.

Is the template free to use without MapTrack?

Yes. Download and use the generator 250-hour service procedure for free. Open the file and use your browser's Print, then Save as PDF. No MapTrack account required. If you later want digital service procedures linked to each generator with scheduling by hours, cost tracking and alerts, we would be happy to show you MapTrack.

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Free generator 250-hour service checklist

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A step-by-step 250-hour (minor) service procedure for diesel generators (stationary and portable). Covers engine oil and filter change, air filter inspection, coolant checks, load bank testing, exhaust inspection, battery and electrical checks, emergency stop testing and enclosure inspection. Includes fluid specifications, parts list and technician sign-off. This page explains what the service involves, how to perform it, and offers a free PDF-ready form you can download straight away.

Last updated: 2026-03-26 · MapTrack

Jarrod Milford

Commercial Director

Updated 26 March 2026

How to use: Fill equipment details and hour reading, then work through each service action. Tick Done as each task is completed. Record fluid quantities and part numbers used. Set the next service due hours and sign off.

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What is a generator 250-hour service?

A 250-hour service is the first tier of scheduled preventive maintenance for a diesel generator. It is performed every 250 engine hours and is classified as a minor service. The procedure covers engine oil and filter replacement, air filter inspection, fuel system maintenance, coolant checks, load bank testing at multiple load steps, exhaust system inspection, battery and electrical checks, emergency stop testing and enclosure condition assessment. Unlike a daily or weekly visual check, the 250-hour service involves actual maintenance actions: draining and replacing fluids, replacing filters, running performance tests and verifying control panel operation. It is typically performed by a qualified generator technician or electrician.

Benefits of scheduled generator servicing

Reliable power when needed: regular oil, filter and coolant maintenance ensures the generator starts and runs at full capacity during power outages or peak demand.
Prevents wet stacking: load bank testing at each service burns off carbon and fuel residue that accumulates when generators run at light load.
Extended component life: clean oil and correct coolant concentration reduce wear on engine, alternator and cooling system components.
Lower repair costs: a 250-hour service costs a fraction of an emergency breakdown repair. Catching issues early prevents cascading damage.
Compliance: documented service records demonstrate that generators are maintained to Australian Standards and WHS requirements, supporting insurance and regulatory obligations.
Resale value: a complete service history with documented 250, 500 and 1,000-hour services increases the generator's value at resale.

Benefits of digitising forms in MapTrack

When you move from paper or static PDFs to digital forms in MapTrack, you get:

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Build conditional logic (show or hide questions based on answers).
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Restrict permissions (who can view, complete or approve).
Build forms with AI (describe what you need and MapTrack suggests the form).

Book a demo to see digital service procedures and hour-based scheduling in MapTrack.

Service actions included in the 250-hour procedure

This service procedure covers 17 service actions across 6 system areas:

Engine: drain and replace engine oil (15W-40), replace oil filter, inspect air filter, drain fuel/water separator, check coolant level and concentration, inspect radiator and hoses, inspect fan belt tension and condition.
Exhaust system: check exhaust for smoke and leaks, inspect exhaust flex couplings.
Electrical: check battery terminals, voltage and electrolyte, check control panel operation and alarms, test emergency stop, check earth connections.
Load testing: run load bank test at 25%, 50%, 75% and 100% rated load.
Mechanical: check vibration isolation mounts, inspect fuel lines and connections.
Enclosure / canopy: inspect vents, louvres and latches.

Fluid specifications

General fluid specifications for diesel generators (stationary and portable). Capacities vary by generator size and manufacturer.

System	Type / Grade	Approx. Capacity
Engine oil	15W-40 CI-4 / CK-4	8 - 20 L (depending on size)
Coolant	50/50 ethylene glycol	10 - 25 L (system)
Grease	EP2 lithium complex	As required

Specifications are general guidelines. Always refer to the manufacturer's service manual for your specific make and model.

Parts and consumables

Have the following parts and consumables ready before starting the 250-hour service:

Engine oil (15W-40 CI-4/CK-4) - 8-20 litres
Engine oil filter - 1
Air filter element - 1 (if replacing after inspection)
Fuel/water separator element - 1
EP2 grease - as required
Coolant (pre-mixed or concentrate) - as required for top-up
Rags, drip tray and waste oil container

Look up part numbers in the manufacturer's parts manual for your specific make and model before ordering.

How to perform a generator 250-hour service

Shut down the generator and allow the engine to cool. Isolate the generator from the electrical supply. Ensure the area is well ventilated.
Record the equipment details and current hour meter reading at the top of the service procedure form.
Start with the engine section: drain the old engine oil, replace the oil filter, fill with new oil to the correct level, then inspect the air filter, drain the fuel/water separator and check coolant level and concentration.
Inspect the radiator and hoses for leaks or damage. Check fan belt tension and condition.
Check battery terminals, voltage and electrolyte level. Check the control panel operation, alarms and earth connections. Test the emergency stop.
Start the generator and run the load bank test at 25%, 50%, 75% and 100% rated load. Record voltage, frequency and temperature readings at each step.
While running, check the exhaust for smoke and leaks. Inspect exhaust flex couplings. Check vibration isolation mounts.
Inspect fuel lines and connections. Inspect the enclosure or canopy, including vents, louvres and latches.
Record any defects or recommendations in the notes section. Set the next service due hours (next 250-hour and next 500-hour intervals). Sign off and update the generator's maintenance log.

In MapTrack, you can schedule services based on hour meter readings, get automatic reminders, complete service procedures on mobile and link every record to the generator. Book a demo to see how.

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Generator service interval hierarchy

Generator maintenance follows a tiered schedule where each level includes all tasks from the level below. This is called carry-forward or cumulative servicing.

250 hours - Minor service (you are here)

Engine oil and filter, air filter inspection, load bank test, exhaust and electrical checks. Estimated 1-2 hours.

500 hours - Intermediate service

All 250-hour tasks plus fuel filter, outer air filter, fan belt replacement, ATS test, protection relay testing, oil sampling. Estimated 2-3 hours.

1,000 hours / annual - Major service

All 500-hour tasks plus coolant flush, injector and valve clearance checks, turbocharger inspection, inner air filter, insulation resistance test, fuel tank drain, vibration analysis. Estimated 4-6 hours.

In MapTrack, you can configure service schedules by engine hours and receive automatic alerts when each interval is due.

Frequently asked questions

What is included in a generator 250-hour service?: A 250-hour generator service is a minor service that includes draining and replacing engine oil (typically 15W-40 CI-4/CK-4), replacing the engine oil filter, inspecting the air filter element, draining the fuel/water separator, checking coolant level and concentration, inspecting the radiator and hoses, checking fan belt tension, running a load bank test at 25%, 50%, 75% and 100% rated load, checking the exhaust for smoke and leaks, inspecting exhaust flex couplings, checking vibration isolation mounts, inspecting fuel lines and connections, checking the control panel, testing the emergency stop, checking earth connections, checking battery terminals, voltage and electrolyte, and inspecting the enclosure or canopy. It takes approximately 1 to 2 hours.
Why is load bank testing important for generators?: Load bank testing verifies that a generator can deliver its rated power output and identifies issues that only appear under load. Running at 25%, 50%, 75% and 100% rated load checks voltage stability, frequency regulation, cooling system performance and exhaust condition. Generators that run on light load for extended periods can suffer from wet stacking (unburnt fuel residue in the exhaust), which reduces performance and damages components. Regular load bank testing at each service interval prevents this and confirms the generator will perform when needed.
What oil goes in a generator engine?: Most diesel generator engines use 15W-40 engine oil meeting CI-4 or CK-4 specifications. Typical engine oil capacity ranges from 8 to 20 litres depending on generator size. Some manufacturers specify different grades for extreme cold or hot conditions. Always check the service manual for your specific make, model and operating environment.
Is the template free to use without MapTrack?: Yes. Download and use the generator 250-hour service procedure for free. Open the file and use your browser's Print, then Save as PDF. No MapTrack account required. If you later want digital service procedures linked to each generator with scheduling by hours, cost tracking and alerts, we would be happy to show you MapTrack.

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