Diesel generators can withstand heavy loads for extended periods, making them reliable and durable pieces of equipment to support your facility’s operations. That said, with typical wear and tear, your supplemental power unit may require maintenance to preserve its integrity.
In this article, you’ll discover a few significant preventative maintenance tips for diesel generators that can guide you in the right direction. If you’d rather have a documented, recurring program in place, our guide on industrial generator preventive maintenance cost breaks down what a professional service plan typically runs, and what to require in a generator maintenance contract before signing one.
Conduct Regular Inspections
To properly maintain your unit, you should conduct routine inspections. This way, you can evaluate key aspects during its operation. While your generator runs, monitor the fuel and exhaust systems, DC electrical mechanisms, and the engine for leakage that could be hazardous to equipment.
For a more organized inspection process, use a diesel generator maintenance checklist to track fuel system condition, oil and filter changes, cooling system health, battery checks, leak risks, and service records before small issues turn into downtime. Before any planned outage or scheduled test, it also helps to run through a dedicated generator pre-start inspection, and to keep a documented generator maintenance log that satisfies NFPA 110 if the unit supports life-safety or standby power. A new unit also benefits from a defined break-in period before it’s put into full service — running it too hard too soon can affect long-term performance.
Change the Oil and Filters
As a crucial maintenance tip, changing your generator’s oil should occur every 100 hours of operation. Doing so can reduce friction within the engine while preventing the device from overheating. The right interval depends on the unit and duty cycle, so it helps to reference actual oil filter selection and change interval guidance rather than a single blanket rule, and to make sure you’re running the right oil viscosity for your diesel generator given your climate and duty cycle. Skipping this step isn’t a minor shortcut — see what actually happens if you skip a generator oil change for how quickly the consequences compound.
Routine oil changes can also help eliminate impurities that accumulate near the engine that impede your equipment’s efficiency. The same discipline applies to fuel filtration — understanding fuel filter change intervals, fuel filter micron ratings, and the broader filter types used across a diesel generator helps prevent premature engine wear, and staying current on EPA and NFPA filter maintenance regulations keeps that work compliant as well. Air intake matters just as much; see our notes on air filter maintenance for guidance on inspection intervals, and don’t overlook the rubber components — our generator belt and hose inspection guide covers the wear points that get missed most often.
Check the Cooling System
You should evaluate the cooling system and fluid levels during the generator’s shutdown period. When coolant within the machine loses its properties, it can affect the engine, causing a decrease in power that can result in the system wearing and the engine failing.
To combat these possible outcomes, you should consider maintaining coolant compartments by adding balanced mixtures of water and antifreeze, and checking supplemental coolant additive levels — our guide on coolant filters and SCA covers what to look for, and our separate piece on coolant testing and freeze protection explains how to verify SCA levels and freeze-point before winter. You can also inspect the radiator’s exterior for dirt and foreign material.
Assess the Fuel Tank
Diesel can be subject to contamination within a year, which is why it helps to conduct generator set exercises as a way to utilize extra fuel. Drain your filters to avoid further water vapor accumulation and condensation within the tank — our breakdown of water separator fuel filters explains how this equipment protects the injection system, and algae and microbial fuel contamination is one of the more common causes of unexplained filter clogging in stored diesel. Running a standby unit too lightly loaded for too long can also lead to wet stacking, which is worth understanding before you set an exercise schedule.
It also helps to inspect charge air cooler pipes and other equipment components for leakages and damages that could affect connections.
Test the Generator Batteries
You want to ensure your generator’s batteries have a full charge since undercharging is a common cause of equipment failure. Regularly test your batteries by performing a load tester assessment to evaluate accurate terminal voltages during performance. If a battery does fail despite regular charging, it’s worth reviewing what causes generator battery failure so the same issue doesn’t repeat with the replacement.
Remember to clean your generator’s batteries if you notice excessive grime and debris accumulation.
Perform Engine Exercise
Performing routine engine exercises maintains the component by keeping it lubricated. These exercises also help mitigate oxidation in electrical contacts and promote a reliable engine start. It helps to conduct assessments once a month for 30 minutes — for the full reasoning behind that cadence, see how often a standby generator should be exercised.
Clean Your Unit
Lastly, you want to clean your generator and ensure you wipe away oil spots, dirt, and debris. There’s a chance you’ll locate pests and insects nesting within your equipment, so remember to conduct frequent checks for these nuisances.
Having a well-designed and well-maintained power unit is paramount for keeping your building operational and productive. By using these preventative maintenance tips, you can keep your diesel generator running for longer by ensuring maximum service life and mitigating costs from mass outages.
Maintaining an industrial diesel generator requires diligence. But it should last a long time when you follow the right steps. Still, there may eventually come a time when you need a replacement unit. Consider Turnkey Industries as your one-stop shop for the ideal unit to supply energy to your facility. Don’t hesitate to contact us with any questions!
