Generator Maintenance Services
A generator that isn’t maintained is a generator you can’t count on. Our preventive maintenance programs keep your backup power system ready for the moment you need it most.
Why Generator Maintenance Matters
Standby generators sit idle for most of their life, waiting for the next outage. During those quiet months, engine oil degrades, fuel breaks down, batteries lose charge, and coolant chemistry shifts. Without regular attention, a generator that ran perfectly during its last exercise cycle may fail to start — or worse, stall under load — when a real emergency hits.
The consequences of a maintenance failure go beyond inconvenience. For businesses, a generator that does not start during a grid outage means lost revenue, spoiled inventory, and potential safety hazards. For hospitals, data centers, and facilities governed by NFPA 110, a failed backup power system can result in regulatory penalties, legal liability, and danger to life.
Regular maintenance extends your generator’s lifespan, preserves your warranty, ensures compliance with fire and building codes, and gives you peace of mind that your investment will perform when the lights go out.
Common Generator Problems We Prevent
Most generator failures are preventable with routine maintenance. Here are the issues we see most often — and how we stop them before they start.
Failure to Start
Dead batteries are the number-one cause of generator no-starts. We test battery voltage, clean terminals, and replace batteries before they fail. We also inspect starter motors, solenoids, and control board connections.
Stalling Under Load
A generator that starts but cannot sustain a load often has fuel delivery problems — clogged filters, degraded fuel, or faulty injectors. We replace fuel filters, test fuel quality, and verify injector performance during every service visit.
Overheating
Low coolant, blocked radiators, failed thermostats, and belt-driven fan issues all cause overheating. Our technicians check coolant levels and chemistry, inspect hoses and belts, and clean radiator cores to ensure proper heat rejection.
Fuel and Oil Leaks
Vibration, thermal cycling, and age cause gaskets, seals, and fuel lines to deteriorate. We inspect all connections, replace worn components, and clean up any existing leaks to prevent fire hazards and environmental contamination.
Wet Stacking
Diesel generators that run at light loads accumulate unburned fuel in the exhaust system — a condition called wet stacking. Left unchecked, it reduces power output and damages engine components. Regular load bank testing burns off deposits and restores performance.
Control System Faults
Modern generators rely on electronic control modules to manage starting, load transfer, and shutdown. Loose wiring, corroded connectors, and software glitches can prevent automatic operation. We inspect and test all control systems during every visit.
Generator Maintenance Best Practices
Our maintenance programs follow manufacturer guidelines and industry best practices. Here is what a comprehensive service visit includes.
Visual and Operational Inspection
Every visit starts with a thorough walk-around. We check the enclosure for damage, verify that air intakes and exhaust are clear, inspect the concrete pad and mounting hardware, and look for signs of rodent intrusion, corrosion, or moisture. We start the generator and listen for unusual sounds, vibrations, or exhaust smoke.
Oil and Filter Changes
Engine oil degrades over time even when the generator runs only during weekly exercise cycles. We change the oil and oil filter according to the manufacturer’s schedule — typically every 200 hours of operation or annually, whichever comes first. We use manufacturer-specified oil grades and OEM filters for optimal engine protection.
Fuel System Service
For diesel units, we test fuel quality, drain water separators, replace fuel filters, and inspect tank vents and return lines. Diesel fuel can degrade in as little as six months, so we recommend fuel polishing or biocide treatment for generators with stored fuel. For natural gas and propane units, we check regulators, valves, and line connections for leaks and proper pressure.
Electrical System Checks
We test battery voltage and specific gravity, clean and tighten all terminal connections, inspect the battery charger output, and verify automatic transfer switch operation. We also check generator output voltage and frequency under no-load and loaded conditions and inspect all wiring for damage, chafing, or loose connections.
Compliance and Documentation
For facilities subject to NFPA 110 or Joint Commission requirements, we maintain detailed service logs that satisfy inspection audits. Every visit generates a written report documenting work performed, test results, and any recommended follow-up actions.
PowerGen Maintenance Programs
We offer flexible maintenance plans designed for different needs and budgets. Every program includes priority scheduling, detailed service reports, and direct access to our service team.
Annual Inspection
One comprehensive service visit per year. Ideal for residential generators with light usage. Includes oil and filter change, battery test, visual inspection, and operational verification.
Semi-Annual Program
Two visits per year for homes and small businesses that want extra assurance. Includes everything in the annual plan plus coolant analysis, belt and hose inspection, and transfer switch testing.
Quarterly Service
Four visits per year for commercial and critical facilities. Includes all standard maintenance plus load bank testing, fuel quality analysis, and NFPA 110 documentation.
Monthly Visual Inspection
Monthly on-site walk-through covering control panel gauges, oil and coolant levels, fuel system, battery condition, cooling system, air induction, and governor. Includes logbook entry at each generator. Ideal for commercial and critical facilities that need documented monthly checks between full service visits.
Predictive Diagnostics: Fluid Sampling & Analysis
Catch problems before they cause failures. Our fluid sampling program sends oil, fuel, and coolant samples to certified laboratories for detailed analysis — revealing wear metals, contamination, fuel degradation, and coolant chemistry issues that visual inspection cannot detect.
Oil Analysis
Detects wear metals (iron, copper, lead), contamination (silicon, water), and additive depletion. Trending oil analysis over time reveals bearing wear, ring blowby, and coolant intrusion before they become catastrophic failures.
Fuel Analysis
Tests for water content, microbial contamination, oxidation stability, and particulate count. Diesel fuel degrades in storage — analysis tells you whether to polish, treat, or replace your fuel before it clogs injectors and filters.
Coolant Analysis
Measures pH, freeze point, inhibitor levels, and dissolved metals. Degraded coolant causes corrosion, liner pitting, and water pump failure. Annual coolant analysis extends cooling system life and prevents expensive engine damage.
Fuel Services
Stored diesel fuel is the Achilles' heel of standby generators. We provide complete fuel lifecycle services to ensure your generator has clean, reliable fuel when an emergency strikes.
Fuel Delivery & Refueling
Scheduled and on-demand diesel delivery to keep your day tanks and bulk storage topped off. We monitor fuel levels and coordinate deliveries so you never run dry during an extended outage.
Fuel Polishing
Removes water, particulates, and microbial contamination from stored diesel. Our mobile polishing units clean fuel in place without draining your tank — restoring fuel quality and extending storage life.
Tank Inspections
Visual and ultrasonic inspection of above-ground and below-ground fuel storage tanks. We check for corrosion, leaks, vent blockages, and regulatory compliance with state and local tank requirements.
Fuel Quality Management
Ongoing monitoring program combining regular sampling, biocide treatment, and polishing schedules to keep your stored fuel within spec year-round.
Testing & Verification Services
Trust, but verify. Our testing services confirm your generator and transfer switch will perform when called upon — not just start, but carry full load and transfer seamlessly.
Load Bank Testing
Resistive load bank testing at 100% of rated capacity for a minimum of 2 hours (4 hours for annual service). Verifies voltage, frequency, amperage, temperatures, and pressures under real-world conditions. Burns off wet stacking deposits in diesel units. Learn more →
Transfer Switch Testing
Simulates utility failure to verify automatic transfer switch operation — including transfer time, retransfer, time delays, and exerciser function. Confirms your building transitions to generator power within NFPA-required time limits. Learn more →
Infrared Thermography
NFPA 70B-compliant infrared scanning of electrical connections, transfer switches, and distribution panels. Identifies hot spots caused by loose connections, overloaded circuits, and failing components before they cause fires or outages. Learn more →
What Does Generator Maintenance Cost?
Maintenance costs depend on your generator's size, fuel type, age, and the scope of service. As a general guide, annual maintenance for a residential standby generator runs $200 to $500 per visit. Commercial generator maintenance ranges from $500 to $2,000+ per visit depending on unit size and compliance requirements.
Compare that to the cost of an emergency repair call — often $1,000 to $5,000 or more — and the cost of a failed generator during an outage: spoiled food, hotel stays, lost business revenue, and potential property damage. Preventive maintenance is one of the best investments you can make in your backup power system.
Frequently Asked Questions
- How often should I have my generator serviced?
- Most manufacturers recommend annual maintenance for residential generators and semi-annual or quarterly service for commercial units. If your generator runs frequently — during outage-prone seasons or for regular testing — you may need more frequent service. We will recommend the right schedule during your first visit.
- How much does a maintenance visit cost?
- Residential maintenance typically runs $200 to $500 per visit, depending on the size and type of your generator. Commercial maintenance ranges from $500 to $2,000+ per visit. Our maintenance programs offer predictable pricing and priority scheduling at a lower per-visit cost than one-off service calls.
- Can I do generator maintenance myself?
- You can perform basic tasks like checking oil level, inspecting the enclosure for debris, and verifying that the battery charger light is on. However, oil changes, coolant service, battery load testing, transfer switch operation, and electrical checks require trained technicians with proper tools and diagnostic equipment. DIY work on electrical systems can be dangerous and may void your warranty.
- What is included in a typical maintenance visit?
- A standard visit includes engine oil and filter change, air filter inspection, battery voltage test, coolant level check, visual inspection of all hoses, belts, and connections, operational run test, and a written service report. Additional services like load bank testing, fuel analysis, and transfer switch exercising are included in our premium programs.
- Do you offer emergency service?
- Yes. PowerGen provides emergency repair service throughout Northern California and Nevada. Maintenance program customers receive priority scheduling and reduced emergency rates. Call us at (209) 229-1990 for immediate assistance.
- Will skipping maintenance void my warranty?
- Most manufacturers require proof of regular maintenance to honor warranty claims. Caterpillar, Kohler, Cummins all specify maintenance intervals in their warranty terms. Our detailed service reports provide the documentation you need to keep your warranty intact.
- What happens if you find a problem during maintenance?
- If we discover an issue during a routine visit, we document it in your service report and discuss repair options with you immediately. Minor issues — a worn belt, a weak battery — can often be resolved on the spot. For larger repairs, we provide a written estimate before proceeding.
- Do you service all generator brands?
- Yes. While we are authorized dealers for Caterpillar, Kohler, Cummins, our technicians are trained to service generators from all major manufacturers including Caterpillar, MTU, Briggs & Stratton, and others. Contact us if you have a brand not listed here — we can almost certainly help.
Related Services
Buy a Generator
Need a new generator? We help you choose the right brand and size for your property.
Learn more →Load Bank Testing
Verify your generator can handle its rated load with professional load bank testing.
Learn more →NFPA 110 Compliance
Ensure your emergency power system meets regulatory requirements with our compliance services.
Learn more →Keep Your Generator Ready
Schedule a maintenance visit today. Our factory-trained technicians will make sure your backup power system is ready when you need it.