Why Diesel Engines Need Water Separators
Diesel fuel and water don’t mix—and that’s a good thing. Unfortunately, water can still find its way into a diesel fuel system through condensation, contaminated fuel, storage tanks, or handling. For diesel engines, even a relatively small amount of water can cause serious problems. That’s why water separators are an important part of diesel fuel filtration.
How Does Water Get Into Diesel Fuel?
Water can enter a fuel system in several ways. Condensation can form inside a partially filled fuel tank as temperatures change. Water can also enter through improperly sealed fuel caps, contaminated storage tanks, or fuel that was already contaminated before it reached the vehicle.
Because diesel fuel is typically stored in tanks for extended periods, water contamination can be particularly troublesome for diesel-powered trucks, construction equipment, agricultural equipment and other heavy-duty applications.
The problem is that water can make its way through the fuel system and reach sensitive components that were designed to be lubricated by clean diesel fuel.
Why Is Water So Harmful to a Diesel Engine?
Modern diesel fuel systems operate at extremely high pressures. Components such as fuel pumps and injectors are manufactured to very tight tolerances, making them particularly vulnerable to contamination.
Diesel fuel provides lubrication for many of these components. Water does not provide the same lubrication. As water passes through the fuel system, it can contribute to corrosion, rust and premature wear.
Water contamination can also cause poor engine performance, hard starting, rough running and, in severe cases, expensive damage to fuel-system components.
The cost of replacing a fuel filter is relatively small compared with the cost of repairing a high-pressure fuel pump or replacing a set of modern diesel injectors.
What Does a Water Separator Do?
A diesel fuel-water separator is designed to separate water from diesel fuel before that water reaches the engine’s fuel system.
The separation process takes advantage of the fact that water is heavier than diesel fuel. As fuel passes through the separator, water and larger contaminants can settle into a collection area, where the water can be drained or removed.
Many diesel fuel filters incorporate water-separation capabilities directly into the filter. Some applications also use a separate water separator in addition to the primary fuel filter.
Some systems have a transparent bowl or water sensor that allows the operator to see accumulated water and know when it needs to be drained.
Don’t Ignore the Water Warning
If your diesel truck or equipment has a water-in-fuel warning light, don’t ignore it. The warning is there because water contamination can become a much bigger—and much more expensive—problem if it is allowed to continue through the fuel system.
Regularly inspecting and replacing fuel filters according to the manufacturer’s recommendations is one of the simplest ways to protect a diesel fuel system. Vehicles operating in harsh environments or equipment that frequently encounters questionable fuel may require additional attention.
FleetFilter Can Help
FleetFilter stocks a wide selection of diesel fuel filters and water-separating filters for trucks, equipment and other diesel applications. We carry filters from trusted manufacturers, including WIX, and can help you identify the correct filter for your particular engine and application. Using the right filter not only helps remove dirt and contaminants—it can also provide an important line of defense against water reaching expensive diesel fuel-system components.
At FleetFilter, our goal is simple: help you find the right filter the first time.