How fuel additives can help diesel engines
Diesel engine vehicles generally run more efficiently than their
gasoline engine counterparts, however the nature of diesel fuel could
cause some drivability problems. Diesel fuel additives can help, but
only as a short-term solution.
Water and dirt in diesel fuel
Diesel issues can begin even before the fuel gets pumped into your tank.
Diesel fuel delivered to gas stations is not necessarily clean and free
of containments. In a 2016 study, Donaldson Filtration Solutions found
that a single delivery of 7,500 gallons of diesel fuel contained one to
two gallons of water and a cup of dirt. Once delivered, even more water
and contaminants can get added to the fuel due to poorly maintained
storage tanks at fuel retailers.
Fortunately, diesel fuel systems have water separators to extract
moisture and fuel filters to capture other contaminants, and both
protect costly fuel injection components and help prevent problems.
Critical maintenance steps for diesel engines are to periodically drain
the water separator and replace the fuel filter.
Be aware of diesel engine drivability issues
Even if you keep up with proper maintenance and use high quality diesel
fuel, your engine still could encounter drivability issues.
Microbial growth – If too much water accumulates in the fuel tank, it
can “fall out” and settle to the bottom of the tank. When this occurs,
bacteria and fungi in the fuel can multiply, forming a black goo that
can plug fuel lines and filters.
Icing – Retained water in the fuel tank or water separator can freeze
in winter, blocking fuel flow and keeping the vehicle from starting.
Fuel gelling – Diesel fuel contains paraffins that congeal in cold
weather, forming a wax-like substance that blocks fuel flow. This
occurs at lower temperatures than icing.
Fuel stability – Diesel fuel stored for long periods can become
unstable and break down, forming gums that clog fuel filters and
create fuel injector and combustion chamber deposits.
Diesel fuel additives help combat these issues. Automakers, however,
caution to use additives as short-term solutions for specific issues,
and not on a continuous basis.
What to know when using diesel fuel additives
Measure twice and treat once. Additives are designed to work with
specific quantities of fuel. For example, 16 ounces of additive may
treat 30 gallons of diesel fuel. Over-treating a fuel system with too
much additive can damage expensive fuel injectors and the injection
Get more for your money. Many additives bundle multiple treatments
into a single product. For example, a diesel fuel “conditioner” may
include the ability to absorb water, an anti-gel agent and a fuel
stability enhancer in one bottle.
A large number of high-quality diesel fuel additives are available
from the aftermarket. Before you purchase any product, consult your
owner’s manual for any special precautions related to using additives.
Automakers test and recommend their own brand of diesel fuel additives
or those of a designated provider. Keep in mind that using a
non-approved additive could void the fuel system or engine warranty if
an occurring problem can be linked to the additive.
Learn more about diesel engines, fuel systems and different types of
additives in AAA’s latest Automotive Technology Update on Diesel Fuel
Find a quality service facility
Whether you need service on a diesel or gas engine, choose a AAA
Approved Auto Repair facility and get the job done right the first time
by a certified auto technician. To know approximately what a repair will
cost, use the online tool to calculate the estimated price including
parts and labor and the AAA member discount.