Updated
What each service includes
Generator Service Intervals Explained
A typical generator schedule has four levels: daily checks of oil, coolant, belts and leaks; draining water from the fuel tank every 50 hours or weekly; an oil-and-filter service every 200 to 500 hours; and deeper major services at multiples of 500 hours on larger diesels. The manual for your engine lists what each level includes.
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- Owner checks you can do
- Technician work by the hour meter
- Calendar items every year
- Onsite across Gauteng
Owner checks and technician work
What happens at each service interval?
The short intervals are owner checks. Perkins lists daily checks of the coolant level, engine oil level, air cleaner service indicator, V-belts and the fuel system primary filter or water separator, plus a walk-around inspection. With the engine stopped and cool, you can look at levels, belts and leaks yourself. Leave the radiator cap closed on a warm engine.
The longer intervals are technician work. At the oil-and-filter service we change the engine oil and the filters that are due, inspect the cooling, fuel and starting systems, read the controller and finish with a run. Perkins schedules this minor service every 500 hours. Generac gives 200 hours or 2 years for its home standby sets, and FEMA course material gives 240 hours for diesels in continuous emergency use.
Major services at 1,000, 2,000, 3,000 and 4,000 hours on a Perkins diesel add the deeper items in the engine manual. We quote that work in writing before we start. To decide how often to book, read our guide to how often a generator should be serviced.
Level by level
What each service level includes
Daily or before each run (you)
Check the oil and coolant levels, the air cleaner indicator, belts and the water separator bowl. Walk around the set and look for leaks, loose guards and alarms on the controller. Perkins lists these as daily checks.
Weekly or every 50 hours (you or us)
Drain water and sediment from the fuel tank where it has a drain. Perkins schedules this every 50 service hours or weekly. Standby diesel collects condensation, so this matters most on sets that sit.
Monthly exercise run (you or us)
Run the set on load. NFPA 110, the US standard quoted by EC&M, calls for diesel sets to carry at least 30% of their standby nameplate rating during the monthly test. A loaded run shows faults that an idle start hides.
Oil-and-filter service, 200 to 500 hours (us)
We change the engine oil and oil filter, replace the fuel and air filters that are due, check coolant, belts, hoses and the battery, read the controller alarms and record the hours. Your manual sets the hour figure for your engine.
Major service, 1,000 hours and up (us)
Larger diesels add deeper work at set multiples. Perkins lists major services at 1,000, 2,000, 3,000 and 4,000 hours. We follow the engine manual’s list for that service and quote it in writing first.
Annual service (us)
A standby set that never reaches its hour limit still needs a yearly visit for the battery, coolant, fuel condition and a loaded run. Generac publishes a yearly maintenance routine for its home standby sets and says to change the oil at least every 2 years, whatever the hours.
Typical published intervals
These are published schedules for particular engines and standards. They show what each level typically includes. Your own engine’s manual gives the exact items and figures for your set.
| Interval | What it includes | Engine or type | Source |
|---|---|---|---|
| Daily | Coolant level, engine oil level, air cleaner service indicator, V-belts, primary fuel filter or water separator, walk-around inspection | Perkins diesel engines | Perkins: How do you maintain a Perkins engine? |
| Every 50 service hours or weekly | Drain water and sediment from the fuel tank | Perkins diesel engines | Perkins: How do you maintain a Perkins engine? |
| Monthly | Exercise run loaded to at least 30% of the standby nameplate rating | Diesel standby sets under US NFPA 110 | EC&M: Testing generators with a portable load bank (quoting NFPA 110, 2013 edition) |
| First 20 hours or 1 month, then 100 hours or 6 months | Engine oil change | Honda portable petrol generators | SlashGear, reporting Honda’s schedule |
| 200 hours or 2 years | Oil and filter change; every 100 hours in very hot or cold conditions | Generac home standby generators | Generac support: home standby maintenance schedule |
| 240 operating hours | Oil and filter change | Diesel generators in continuous emergency use | FEMA IS-815: generator servicing requirements |
| 500 hours | Minor service | Perkins diesel engines | Perkins: How do you maintain a Perkins engine? |
| 1,000, 2,000, 3,000 and 4,000 hours | Major services | Perkins diesel engines | Perkins: How do you maintain a Perkins engine? |
| Yearly | Yearly maintenance routine; oil changed at least every 2 years regardless of hours | Generac home standby generators | Generac support: yearly maintenance for home standby generators |
| Yearly, if the monthly 30% load is not reached | Load bank run at 50% of nameplate kW for 30 minutes, then 75% for 60 minutes | Diesel standby sets under US NFPA 110 | EC&M: Testing generators with a portable load bank (quoting NFPA 110, 2013 edition) |
Check your own hours and dates in our service due checker. For how often to book, standby against prime, and what brings a service forward, read how often a generator should be serviced.
Related Pages
Frequency, hours and servicing
- Service Due Checker Check hours and dates against the interval
- How Often to Service How often to book, standby against prime
- Running Hours The meter the schedule uses
- Service Checklist What we check at a service
- Diesel Maintenance Checklist Daily, weekly and 500-hour diesel work
- Generator Servicing Book the service that is due
Common Questions
Questions about generator service intervals
What is included at each generator service interval?
Typically, daily checks cover oil, coolant, belts and leaks; weekly or 50-hour work drains water from the fuel tank; and the 200- to 500-hour service changes the oil and filters. Larger diesels add major services at 1,000 hours and up. Your engine manual lists each level for your set.
What can I check myself between services?
With the engine stopped and cool: the oil level, the coolant level in the expansion tank, belts, the air cleaner indicator, visible leaks and any alarm on the controller. Leave filter changes, electrical tests and anything under a hot radiator cap to us.
What happens at a 500-hour service?
On a Perkins diesel, 500 hours is the minor service. We change the engine oil and the filters that are due, inspect the cooling, fuel and starting systems, read the controller and finish with a run test. The engine manual lists the exact items.
What is a major service?
A deeper service at a larger multiple of hours. Perkins lists major services at 1,000, 2,000, 3,000 and 4,000 hours. We follow the engine manual’s list and quote the work in writing before we start.
What is a first service?
An early oil change on a new or rebuilt engine. Honda’s portable schedule, as reported by SlashGear, sets it at 20 hours or 1 month, before the routine 100-hour interval starts.
What does an annual service include?
We change the oil and filters if they are due, test the battery and charger, check coolant, belts, hoses and fuel condition, read the controller and run the set on load. It covers the calendar items on standby sets that run few hours.
Do standby generators need weekly checks?
Yes, quick ones. Look at levels, leaks and the controller each week. Perkins schedules draining water from the fuel tank every 50 hours or weekly, because condensation collects in standby diesel tanks.
How do I find the right intervals for my engine?
Read the engine model from its plate and open that manufacturer’s maintenance schedule. Send us a photo of the plate and we plan the visit around it.
Still unsure what the fault is? Call or WhatsApp 082 057 4605 for onsite diagnosis.
Service Areas
Onsite visits across Gauteng
We come to your generator anywhere in Gauteng, 24/7. Choose your region for local suburbs, call-out details and the faults we see most there.
What to send before we attend
These details help us plan the visit and bring the right parts. Send what you can on WhatsApp; if you can’t find the model number, we still book the visit.
- Location
- The suburb or site, so the visit can be booked in the right area.
- Make and model
- The generator brand and model, if they are known.
- kVA
- The size printed on the data plate.
- Fuel type
- Diesel, petrol, LPG, natural gas, or dual-fuel.
- Controller model
- The module name on the panel, when it is visible.
- Fault or alarm
- What the set does, and any text on the screen.
- Photos
- The generator, the data plate, and the controller or alarm. Send these on WhatsApp.
Book a Visit
Send the plate and the hours
With the engine model and the hour reading, we follow the schedule for your engine and bring the right parts.
- Call
- 082 057 4605
- Message us on WhatsApp
What happens next
- We reply with questions about the generator, or to book a visit.
- A technician comes to you. For a breakdown we arrive within 1 hour.
- The fault is diagnosed on site and you get a written quote. No work starts until you accept it.
Charlie, lead technician: Degree in Mechanical Engineering, Degree in Electrical Engineering, Diesel Plant Fitter. Generator specialists since 2000.