Inspect the Diesel Fuel in your Generator Once a Year

Why Inspecting Diesel Fuel is Key in Your Commercial Generator Preventive Maintenance

For building engineers, ensuring every piece of equipment runs smoothly is essential, and that includes the all-important commercial generator. But while many maintenance routines focus on parts like filters, belts, and battery checks, there’s one often-overlooked component that deserves attention: diesel fuel.

Diesel might seem straightforward—after all, it’s just fuel, right? But fuel quality and cleanliness play a significant role in your generator’s performance. By inspecting the diesel fuel regularly, you not only extend the generator’s life but also ensure it performs as expected when needed most. Let’s dive into why fuel inspections should be a top priority in your preventive maintenance checklist.

Diesel Fuel Degradation: A Hidden Issue

One of the biggest issues with diesel fuel is that it degrades over time. A generator might sit unused for weeks or even months, and in that time, the diesel fuel stored in the tank can start to break down. Why does this matter? Because degraded fuel can lead to clogs, deposits, and even corrosion in the fuel system. Over time, these deposits build up in key components like fuel injectors and pumps, ultimately impacting the generator’s ability to start and run efficiently.

How does fuel degradation happen?

Diesel fuel contains organic compounds that naturally attract microbes—specifically bacteria and fungi. These microbes thrive in water, and even a small amount of moisture in the fuel tank (from condensation, for example) can create a breeding ground. As microbes multiply, they form sludge and slime that can clog fuel filters and injectors, impacting fuel flow and potentially leading to a generator failure when you need it most.

Detecting Fuel Issues Early

When you’re doing preventive maintenance on a generator, inspecting diesel fuel goes beyond just looking at its color. Here are the main things to keep an eye on:

1. Water Content: Water is a major contaminant in diesel fuel, and even trace amounts can lead to microbial growth and corrosion. During fuel inspections, use a water detection kit or check for phase separation—where water separates and settles at the bottom of the tank.
2. Microbial Growth: As mentioned, microbial growth leads to sludge and other contaminants in the fuel. Testing for microbes involves taking a sample and testing it for signs of bacteria and fungi. If microbial contamination is detected, fuel polishing or biocide treatment may be necessary to restore fuel quality.
3. Sediment and Sludge: When diesel degrades, it can leave behind sediments that clog filters and injectors. Inspecting for sediment is as simple as checking a fuel sample for any visible particles or cloudiness, which indicate impurities that could impact generator performance.
4. Fuel Stability: Diesel’s stability can decrease over time, leading to issues like the breakdown of chemical compounds within the fuel. This is more difficult to detect on-site, but fuel stability testing can be outsourced to a lab for a detailed analysis. Stabilizers are often added to fuel to keep it fresh, but these have limits, so regular testing is wise.

Why Regular Fuel Inspections Matter

Failing to monitor diesel fuel quality can turn minor issues into costly repairs down the line. Clean fuel ensures smooth combustion, better fuel economy, and ultimately, the reliability of your generator. A generator failing to start in an emergency can be disastrous—especially in facilities that rely heavily on uninterrupted power, like hospitals, data centers, and manufacturing plants.

Routine fuel inspections let you catch any issues before they turn into serious problems. For instance, if you notice an uptick in water content or detect sludge, you can address it with fuel polishing or tank cleaning, keeping your fuel in optimal condition.

Taking Action: How to Handle Contaminated Fuel

So, what should you do if you find contamination in your diesel fuel? Here’s a quick rundown of potential remedies:

1. Fuel Polishing: This process removes contaminants by filtering the fuel multiple times. It’s especially effective for sediment and sludge but also addresses water content and microbial contamination to some extent. But, as Duthie Power’s Safety and Quality Assurance Manager Johnny Bradford points out, it’s important to manage your expectations when it comes to fuel polishing. “Fuel polishing is only a preventative measure to keep good fuel good; it does not repair or correct bad fuel. Once fuel is bad, it can’t be reconditioned and must be replaced.”
2. Tank Cleaning: For more severe contamination, tank cleaning may be necessary. This involves draining the tank, cleaning it thoroughly, and refilling it with fresh fuel. It’s more labor-intensive but essential if sludge and microbes have built up significantly.
3. Fuel Additives: Adding stabilizers or biocides to fuel can help prevent degradation and microbial growth. However, these are preventive measures rather than solutions, so they’re best for maintaining already clean fuel rather than fixing contaminated fuel.

The Bottom Line

Diesel fuel inspection is a critical yet often underestimated part of generator maintenance. By adding regular fuel quality checks to your preventive maintenance routine, you’re ensuring that your generator is ready to perform at its best whenever called upon. Think of it as an investment in reliability, safety, and peace of mind, knowing that when an emergency strikes, your power source won’t let you down.

For building engineers, understanding the importance of diesel fuel quality helps you stay a step ahead, avoiding downtime, saving on repair costs, and ultimately keeping your building powered and protected.

To book a diesel generator inspection for your facility, request a maintenance quote or give us a call at 1-800-899-3931