Biodiesel - GMC Terrain 2018 Owner's Manual

236 Driving and Operating
Caution (Continued)
locomotive, or boiler distillate fuel
since it may contain higher sulfur
levels.

Biodiesel

Biodiesel is a renewable fuel
produced from vegetable oils or
animal fats that have been
chemically modified to make it
compatible with diesel fuel.
Caution
Do not use home-made biodiesel
or home test kits because the
quality cannot be verified by
approved scientific methods. Do
not use raw vegetable oil or other
unmodified bio-oils, fats,
or blends of vegetable oil with
diesel. They could damage the
fuel system and engine, and
damages would not be covered
by the vehicle warranty.
Caution
Do not use blends containing
more than 20% biodiesel. Any
engine, fuel system, or exhaust
after-treatment system damage
would not be covered by the
vehicle warranty.
Biodiesel fuel quality degrades with
time and exposure to high
temperature quicker than Ultra Low
Sulfur Diesel fuel. More frequent
refueling provides the best
opportunity to have a supply of fresh
fuel. Storage at hot ambient
temperatures will accelerate
biodiesel degradation.
Owners who use very little fuel,
or who have vehicles stored for
extended periods of time, should
avoid the use of biodiesel blended
fuels above 5% by volume. When
vehicles are stored for longer than
one month, they should be run out
of biodiesel to below one-quarter
tank, refueled with Ultra Low Sulfur
Diesel fuel, and driven at least
32 km (20 mi) before storage.
At temperatures below 0 °C (32 °F),
it is recommended to switch to Ultra
Low Sulfur Diesel fuel with no
biodiesel content, or to blends with
biodiesel containing less than 5% by
volume. At these extreme cold
temperatures, biodiesel blends
higher than 5% by volume may
cause fuel filter plugging and
system gelling, which can lead to
vehicle operability problems.
Fuels improperly blended for cold
temperature operation may result in
restricted fuel filters and degraded
vehicle performance. GM diesel
vehicles are equipped with a fuel
heating system to provide an extra
level of protection against filter
plugging from gelling or waxing of
conventional diesel fuel and
biodiesel blends. If the operating
temperature is far below the
temperature at which gelling or
waxing of the fuel occurs, the
system cannot prevent all cases of
filter plugging.
If the vehicle experiences a fuel
filter restriction, the on-board
monitoring system will alert the
driver that the fuel filter requires