Why Intervals Exist
Every piece of heavy machinery has a manufacturer-defined service schedule. These intervals are based on engine hours and exist because different components wear at different rates and need attention at different times.
Engine oil degrades faster than hydraulic fluid. Air filters clog faster than fuel filters. The interval system ensures each component gets serviced at the right time, not too early and not too late.
Hours, Not Kilometres
Heavy plant does not track kilometres the way road vehicles do. An excavator might sit in the same spot for weeks, running 10 hours a day under full load. The engine is doing serious work, but the odometer has not moved.
Engine hours are the real measure of wear. Every manufacturer service schedule for excavators, loaders, dozers, graders, and other heavy plant is built around hours.
The Core Intervals
The four standard intervals for most heavy machinery are 250, 500, 1000, and 2000 hours. As Fortis HD outlines in their comprehensive service guide, each service mark "will always include draining and replacing all fluids" relevant to that interval level. Fresh oil allows machines to run more smoothly and protects internal components from premature wear.
250-Hour Service
This is your routine maintenance. It is the equivalent of a standard oil change on a car. Quick, straightforward, and something a competent operator or in-house mechanic can handle.
What is covered:
- Engine oil and filter change - oil breaks down under heat and load. By 250 hours, it is done.
- Grease all points - every pin, bush, bearing, and pivot point on the machine
- Belt and drive chain tension check - adjust or replace if needed
- Axle oil level check - top up as needed
- Check all fluid levels - hydraulic oil, coolant, transmission fluid, differential oil
- Visual inspection of belts and hoses - looking for cracking, fraying, rubbing, or leaks
- Air filter check - inspect the outer element, check the restriction indicator
- Drain water from fuel separator - water in diesel causes injector damage
- Walk-around inspection - general condition check of the machine structure, undercarriage, and attachments
Time required: 1 to 2 hours for a competent mechanic with parts on hand.
500-Hour Service
This builds on the 250-hour service. Everything in the 250 gets done, plus additional items that need attention at the longer interval.
EquipmentShare emphasises that oil sampling at 500 hours is a critical addition. They recommend taking "samples of engine oil, hydraulic oil, transmission oil, travel gear case oil, coolant, and fuel for analysis." This baseline sample is one of the most valuable diagnostic tools for heavy machinery.
Additional items at 500 hours:
- Oil sampling - engine oil, hydraulic oil, transmission oil, and coolant samples sent to a lab for analysis
- Hydraulic filter replacement - the hydraulic system is the lifeblood of any excavator or loader
- Fuel filter replacement - primary and secondary fuel filters changed. Dirty fuel is the number one killer of modern diesel injectors.
- Hydraulic pump check - inspect for leaks, unusual noise, and performance
- Air intake inspection - detailed check beyond the standard filter check
- Radiator condition - check for blockages, leaks, and fin damage
- Cabin air filter replacement - for operator comfort and health
- Battery condition check - terminal condition, voltage under load
- Detailed undercarriage inspection (tracked machines) - measure track pad wear, check roller and idler condition
- Fan belt tension and condition - adjust or replace if worn
- Hydraulic hose inspection - detailed check of all hoses, especially near heat sources
Time required: 3 to 4 hours.
1000-Hour Service
This is a major service. It covers everything from the 250 and 500, plus deeper inspections and fluid changes.
Additional items at 1000 hours:
- Drive chain case oil replacement - fresh oil for the final drive system
- Fuel tank sump drain - remove accumulated water and sediment from the bottom of the fuel tank
- Hydraulic reservoir oil replacement - full change of the hydraulic system oil
- Hydraulic oil filter replacement - changed in conjunction with the full oil change
- Coolant system flush and refill - coolant degrades over time, losing its corrosion inhibitors
- Engine and hydraulic oil samples - compared against the 500-hour baseline to identify trends
- Valve clearance check - on engines that require it
- Full electrical system inspection - wiring, connectors, alternator output, starter motor condition
- Brake system inspection - service brakes, park brake, and emergency brake
- Turbocharger inspection - check for shaft play, oil leaks, boost pressure
- Swing bearing and slew ring inspection (excavators) - check for play, grease condition, bolt torque
Time required: Full day or more. Often requires a qualified heavy diesel mechanic with diagnostic equipment.
The 1000-hour service is where you find developing problems before they become catastrophic failures. Cutting corners here costs you later.
2000-Hour Service
The comprehensive overhaul. Everything from every previous interval, plus deep-dive items that assess the long-term health of the machine.
Additional items at 2000 hours:
- Engine inspection - compression test, injector testing, cylinder head check
- Turbocharger service - detailed inspection or rebuild depending on condition
- Complete hydraulic system evaluation - pump flow testing, valve response, system pressure checks
- Full undercarriage assessment (tracked machines) - detailed wear measurements against manufacturer specs
- Swing bearing replacement assessment - based on play measurements and grease sample analysis
- Complete structural inspection - boom, stick, chassis, and frame checked for cracking and fatigue
- Transmission service - full fluid change, filter replacement, and clutch pack inspection
Time required: Multiple days. This is typically a workshop job.
Why Intervals Are Additive
This is the concept that trips people up. Services are additive, not standalone. When a machine hits 500 hours, you are not just doing the 500-hour items. You are doing the 250-hour service plus the 500-hour items on top.
How It Works
- At 250 hours: 250-hour service
- At 500 hours: 250-hour service + 500-hour additional items
- At 750 hours: 250-hour service (another 250-hour cycle)
- At 1000 hours: 250-hour service + 500-hour additional items + 1000-hour additional items
- At 1250 hours: 250-hour service
- At 1500 hours: 250-hour service + 500-hour additional items
- At 2000 hours: Everything. All four intervals at once.
You cannot skip a 250 and jump to 500. If a machine reaches 480 hours and the 250-hour service was not done, that engine has been running for 230 hours on degraded oil. The 500 at that point does not undo the damage from the missed 250.
Oil Sampling: Your Early Warning System
Oil sampling gets more revealing as the intervals increase.
At 500 Hours
The first sample establishes a baseline for the machine. It shows normal wear metal levels when everything is working correctly.
At 1000 Hours
Now you are comparing against the baseline. Trending begins here. Are wear metals increasing? Is contamination present?
At 1500 and 2000 Hours
The trend line becomes clear over multiple samples. This data feeds directly into predictive maintenance, scheduling repairs before a failure occurs rather than reacting after the machine breaks down.
What the Lab Reports Tell You
- Iron - cylinders, rings, camshaft
- Copper - bearings, oil cooler tubes, bushings
- Lead - bearing overlay material. Elevated lead often means bearing failure is approaching.
- Silicon - dirt ingress. High silicon means the air filter or a seal has failed.
- Coolant contamination - glycol or water indicates a head gasket or liner seal issue. Needs immediate attention.
Parts Prep and Lead Times
Each interval requires different parts. Order when the machine hits the "prep zone," typically 50 to 100 hours before the service is due. If you wait until the machine hits the interval, you will be chasing parts while the machine sits idle.
Time-Based vs Hours-Based
Some machines do not accumulate hours quickly. A generator used for backup power might only run 50 hours a year.
Most manufacturers specify "whichever comes first" for service intervals. A machine that has only done 100 hours in a year still needs the annual service items completed. Fluids degrade over time regardless of use. Rubber hoses deteriorate. Seals dry out.
Your tracking system needs to handle both triggers.
Keeping It All Straight
Managing service intervals across a fleet of 10, 20, or 50 machines, each at different hours and on different cycles, is genuinely complex. This is where manual tracking falls apart.
Burgy tracks every service interval for every vehicle in your fleet with visual gauges showing hours remaining until each service level. Daily prestart readings feed directly into the countdown, so the data is always current. Prep zone alerts give you advance warning to order parts and book workshop time before a machine hits its interval. Complete service history, including oil sample results, parts used, and costs, is stored against every vehicle.