Cleaning a Generator’s Diesel Fuel Tank

Cleaning a diesel fuel tank on a generator is one of those essential maintenance tasks that can extend your equipment’s lifespan, prevent unexpected shutdowns, and save you a lot of headaches down the line. Over time, contaminants like water, sludge, and microbial growth (yes, even bacteria can thrive in diesel!) can build up in the tank, leading to clogged filters, corroded components, and overall performance issues. Let’s break down how to clean the tank and what you can do to keep it in great shape for years to come. 

**DISCLAIMER: Below is an overview of the steps involved in cleaning a diesel fuel tank, but we highly recommend securing the services of a professional to ensure optimum safety and compliance with environmental standards.**

How to Clean a Diesel Fuel Tank

Step 1: Safety First
Before getting started, make sure you’re working in a well-ventilated area. Diesel fumes can be hazardous, so it’s crucial to have proper ventilation. Wearing gloves, safety glasses, and protective clothing is also a must. Ensure that all electrical connections are turned off and that the generator is cool before starting.

Step 2: Drain the Tank
The first step is to drain the diesel fuel from the tank. If the fuel is still in good condition and free from contaminants, you can store it temporarily in a clean, sealed container. However, if the fuel has signs of contamination like cloudiness or a foul odor, it’s better to dispose of it according to local hazardous waste disposal guidelines.

This step may not always be needed or prudent. As Duthie Power Sales Engineer Pete Thornton explains in the video above, “When you clean your diesel tank you want to have it full of fuel (so you’re cleaning the entire tank). When you clean it there is a device that goes down like a snake into the tank. It vibrates and goes all the way around the tank banging the sides and the bottom to loosen the algae growth and dirt that has accumulated. The next thing to do is draw the fuel out of the tank through a filter system and then back into the tank.”

Now, if filtering the fuel isn’t enough to remediate the issues in your fuel tank, continue on to Step 3.

Step 3: Inspect and Clean the Inside of the Tank
Once the tank is empty, open any inspection ports if available. Use a flashlight to look inside and assess the level of buildup or contamination. You might see sludge (a mixture of water, dirt, and microbial growth) settled at the bottom or clinging to the walls.

Using a combination of brushes, rags, and a vacuum designed for hazardous liquids, scrub the interior to remove as much debris as possible. If sludge is particularly thick, you may need a special fuel tank cleaning solution. These solutions help break down the buildup, making it easier to clean out. Be thorough with this step, as leftover contaminants can quickly cause issues once the tank is refilled.

Step 4: Flush and Rinse
After scrubbing, rinse the tank with a small amount of clean diesel or a specialized rinsing agent. This helps ensure that any remaining loose particles are washed out. Drain the rinse completely before moving on.

Step 5: Replace Filters and Check Seals
Once the tank is clean, it’s a good idea to replace the fuel filters. Contaminated filters can reintroduce dirt and microbes into the clean tank. Also, inspect the tank’s seals and gaskets. If they’re cracked or worn, replace them to avoid leaks or contamination down the road.

Preventive Measures for Long-Term Cleanliness

Now that your tank is spotless, the goal is to keep it that way. Here are some key practices to help maintain clean fuel for years to come:

1. Regular Inspections: Schedule regular tank inspections, especially in humid or wet environments. Moisture is the enemy, and even small amounts can lead to microbial growth and corrosion.
2. Fuel Quality Matters: Always use high-quality, fresh diesel from a trusted supplier. Diesel has a shelf life, and old or contaminated fuel can introduce problems right from the start.
3. Fuel Polishing: Also called “Fuel Scrubbing,” this process cleans out all the water and contaminants, including algae growth. Pete adds, “After this process you will have the best quality fuel in your tank. You can fuel polish tanks anywhere from a small 20 gallon tank to a 10,000 gallon tank.” Every year the fuel should be tested in the tank. We generally suggest a fuel polishing at least every 3 years.
4. Water Control: Use fuel-water separators and keep an eye on any signs of water accumulation in the tank. Even small amounts of water can lead to microbial growth, which produces sludge and acids that damage the tank and fuel system.
5. Stabilizers and Biocides: Adding fuel stabilizers and biocides to your diesel can prevent the growth of microbes and help maintain fuel integrity. Just be sure to follow the manufacturer’s instructions when using these additives.
6. Proper Storage: If your generator isn’t used frequently, consider using a fuel maintenance system or periodically running the generator to keep the diesel from becoming stagnant. Stagnant fuel is more prone to contamination and degradation.
7. Tank Ventilation: Ensure that the tank’s ventilation system is functioning correctly. Poor ventilation can lead to condensation inside the tank, contributing to water buildup and contamination.

Wrapping It Up

Cleaning a diesel fuel tank isn’t the most glamorous task, but it’s one of those jobs that pays off in the long run. With regular cleanings and the right preventive measures, you can keep your generator’s fuel system running smoothly and avoid costly repairs or downtime. Taking the time to keep your tank clean now will save you from dealing with common generator fuel tank problems later.

For more information on cleaning a diesel fuel tank, give us a call at 1-800-899-3931 or request a service quote. Learn more about how to keep a commercial generator clean online.