Low-Viscosity Lubricants
A Glance at Clean  Freight Strategies
      ENERGY &

     Gallons Saved:
       485 gallons
      CO2 Savings:
    4.93  metric tons
   Fuel Cost Savings:
Synthetic lubricants in the engine crankcase, rear axle, and transmission can
improve fuel economy by about 3 percent, saving nearly 485 gallons of fuel and
eliminating 5 metric tons of greenhouse gas emissions for a typical combination
truck each year.

What is the challenge?
Lubricants reduce friction and wear of critical vehicle systems including the engine, transmission
and drive train. Without lubricants, the moving parts inside these systems would grind together,
causing heat, stress and wear. Conventional mineral oil lubricants may have too high viscosity
(internal friction that resists sliding and inhibits flow) to effectively slip between and lubricate the
moving parts of these systems, particularly in newer truck components that are designed with
close tolerances and tight fits. Conventional lubricants may also be heavy, making it harder for
pumps, gears and shafts to move. These effects create energy losses and friction losses,  and
waste fuel.

What is the solution?
Low-viscosity lubricants are less resistant to flow than conventional  lubricants, a property that
helps reduce friction and energy losses. Depending upon  the application, low-viscosity lubricants
may also contain additives designed to withstand the extreme pressure (EP) that could occur as
the lubricant flows between tight-fitting parts. Low-viscosity lubricants may be made from synthetic
or mineral oil blends with low-viscosity and EP additives. Manufacturers generally offer low-
viscosity blends as "fuel economy" lubricants, since the fuel-saving potential  of these products is
significant. A national trucking association reports that synthetic  transmission  and axle lubricants
can improve fuel economy by 0.5 percent in the summer  and 2 percent in the winter (viscosity
is temperature-dependent.) A paper published by a professional engineering society found that
synthetic engine and transmission lubricants could improve fuel  economy by  5 percent, with
greater gains at lower speeds. Another paper from this same organization reports that synthetic
gear lubricants can improve fuel economy by about 3 percent. European research demonstrates
a 3 to 5 percent gain in truck fuel economy using low friction engine lubricants and a 1  to 4
percent gain using low friction transmission lubricants.
Synthetic and semi-synthetic lubricants typically cost more  than conventional  mineral oil
lubricants. Truck service stations suggest that semi-synthetic oils cost about 50 percent more than
   conventional mineral oils. However, for most trucks, the fuel cost savings generally outweigh
      the higher product cost. Furthermore, synthetic lubricants may extend  the interval between
        lubricant changes therefore further reducing costs of truck fleets.
                                           Savings  and  Benefits
                                             The combined effect of low-viscosity synthetic engine oils and drive train
                                              lubricants can improve fuel economy by at least 3 percent, saving nearly
                                              485 gallons of fuel per year for a typical combination truck. Even with the
                                              higher cost of the synthetic oil, truck owners can save more than $1,680
                                              in fuels per year. Additional cost savings may be possible due to reduced
                                              wear and maintenance. Switching to low-viscosity lubricants will reduce
                                             greenhouse gas emissions by 4.93 metric tons per year for each truck.

                                     U.S. EPA SmartWay |  EPA-420-F-16-027 | June 2016 |

Idle Reduction
A Glance at Clean Freight Strategies

1        Trucking com-
        panies should
     consider using low-
     viscosity lubricants to
     improve fuel econo-
     my. Synthetic oils are
     compatible with most
     truck systems, save
     fuel, and should
     provide net cost
2   Before switch-
   ing lubricants,
trucking companies
should ensure that
the product suits the
intended application.
Always check manu-
facturer specifications
before switching
engine, transmission
or drive train
3Consult the
vehicle and parts
owner manuals and
service manuals for
information and
recommendations on
lubrication specifica-
tions and procedures.
Lubricating oil manu-
facturers and lubri-
cation guides can
provide information
about product appli-
4Trucking associa-
   tions, equipment
manufacturer asso-
ciations and trucking
industry publications
may provide addi-
tional information
and case studies
about the benefits
and uses of various