Testing Keeps Back-up Generators Functional for Emergency Situations

Oil Testing 

Oil analysis for emergency backup generators helps ensure reliability, performance and longevity – all essential for equipment that must start and run. Emergency generators often sit idle for long periods, then have to operate seamlessly under very high loads. Oil analysis will detect early signs of problems, such as wear metals or contamination, that could cause failure.  

Even without use, oil naturally degrades and can become contaminated by moisture, fuel, soot or coolant leaks – particularly in diesel systems. Testing catches these issues before they lead to engine damage. 

Monitoring oil condition also allows for data-driven maintenance rather than relying solely on time-based change intervals. This approach helps prevent premature wear and reduces the risk of catastrophic engine failure. In addition, many facilities – such as hospitals, data centers and utilities – must meet regulatory guidelines for generator readiness. Documented oil analysis helps demonstrate compliance and supports maintenance records for audits or insurance claims. Recommended oil tests for generators include: 

• Viscosity: Ensures the oil maintains proper thickness for lubrication;  
• Acid number/base number: Measures oil acidity or its ability to neutralize acids, indicating oil degradation or remaining life; 
• Fuel dilution: Identifies unburned fuel contamination that can reduce lubrication and cause damage; 
• Water content: Indicates potential coolant leaks or condensation issues that can cause rust or corrosion; 
• Oxidation: Measures oxidation due to heat exposure, which can affect oil performance; 
• Particle count: Especially useful in high-performance or critical power systems, this test checks oil cleanliness and helps prevent abrasive wear; 
• Elemental spectroscopy: Measures the amount of key elements related to wear, additives and contaminants.  

These tests can be performed as part of a preventive maintenance program and are especially critical for backup generators that may sit idle for long periods but need to perform at a moment’s notice. 

Ultimately, oil analysis can significantly reduce long-term costs by providing early warning of problems. It helps avoid expensive repairs, unplanned downtime and emergency service calls when failure happens during a crisis. 

Fuel Testing

Fuel testing for emergency backup generators is also essential. Even more so than oil quality, fuel quality directly impacts whether the generator will start and run when needed.  

Diesel fuel degrades over time, especially when stored for long periods. Testing helps detect oxidation, sludge and microbial growth – such as bacteria and fungi – that can clog filters, damage injectors and ultimately prevent the generator from starting.  

In addition, contaminants such as water, dirt and particulate can cause serious damage to the fuel system and engine components. Regular testing helps catch these problems before they lead to costly repairs or failure during operation. 

Water contamination, in particular, is a common issue with fuel, often resulting from condensation in storage tanks. It can encourage microbial growth and corrosion. Fuel testing detects and addresses water before it becomes a serious threat. Testing also verifies that fuel still meets key performance standards such as cetane rating, sulfur content and flash point, all of which are necessary for reliable combustion, optimal power output and emissions control. 

Following are recommended fuel tests.  

• Karl Fischer water content: Detects water that can cause microbial growth, rust and injector damage; 
• Microbial contamination (bacteria, fungi): Identifies biological growth that forms sludge and biofilm in fuel tanks; 
• Particle count: Measures solid debris that can clog filters and damage injectors; 
• Fuel stability: Checks for fuel degradation over time – especially important for stored diesel; 
• Flash point: Ensures safety by measuring volatility and ignition characteristics; 
• Cetane number: Indicates ignition quality – important for cold starts and smooth performance; 
• Sulfur content: Verifies compliance with ultra-low-sulfur diesel regulations; 
• Viscosity: Ensures proper fuel processing and injector performance. 

Ultimately, proactive fuel testing helps reduce unplanned downtime, avoid emergency service calls and prevents the high costs associated with fuel-related failures and system clean-up. 

Coolant Testing

When coolant becomes degraded, it can lead to overheating – one of the most common causes of generator failure during operation. Over time, coolant also loses its ability to inhibit corrosion, control pH and prevent scale buildup. Testing helps detect issues such as acidification, additive depletion and glycol breakdown before they can damage internal engine components. 

Contamination is another critical concern for coolants. It can be compromised by oil, fuel or minerals such as those found in hard water, all of which reduce cooling efficiency and can lead to clogging or corrosion in radiators, water pumps and cylinder liners. Regular testing supports overall system longevity by maintaining proper freeze and boil protection, corrosion resistance and cleanliness – extending the life of the engine, seals, gaskets and heat exchangers. 

Following are recommended coolant tests for generators. 

• pH level: Indicates acidity or alkalinity. A drop in pH can lead to corrosion of metal components; 
• Freeze point: Confirms that the coolant concentration is adequate to prevent freezing in cold conditions; 
• Boiling point: Ensures the coolant won’t evaporate or boil over under high-temperature operation; 
• Nitrite, molybdate and other additives: Tests the levels of corrosion inhibitors. Low levels indicate that the coolant is no longer protective; 
• Chloride and sulfate contamination: Detects water or air ingress that can cause corrosion or pitting; 
• Glycol concentration: Measures the glycol-to-water ratio, critical for heat transfer and protection from freezing; 
• Total dissolved solids: Measures the accumulation of debris, corrosion products and scale-forming materials; 
• Visual inspection: Identifies oil contamination, discoloration or particulate matter by sight. 

These tests are vital for both diesel- and gas-powered generators, particularly those that run in demanding environments or serve as critical backup systems. Regular coolant analysis helps extend engine life, reduce maintenance costs and ensure generator readiness. As with oil and fuel testing, documented coolant testing helps organizations comply with regulatory standards, satisfy insurance requirements and maintain thorough maintenance records for audits and inspections. 

Together, regular oil, fuel and coolant testing form a predictive maintenance strategy that reduces costly repairs and ensures the generator is always available.  These tests can be performed as part of a preventive maintenance program and are especially critical for backup generators that may sit idle for long periods but need to perform instantly when required.  

Mary Messuti is president of Eurofins TestOil Inc., located in Strongsville, Ohio, United States. She has over twenty five years of experience in laboratory management as well as heavy industrial and aerospace manufacturing environments.