Cold Weather Operation - Chevrolet 4500 HD 2023 Manual

Biodiesel Blends
Use biodiesel blends that meet the ASTM
specification D6751.
Retail pumps dispensing blends containing
up to 5% biodiesel (B5) are not required to
be labeled with the concentration of
biodiesel. Blends up to B5 must meet ASTM
D975 (Grades No. 2-D or No. 1-D S15 Ultra
Low Sulfur Diesel). When refueling with a
biodiesel blend above B5, one of the
following labels should appear on the
dispenser:
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.
Blends containing more than 5% and up to
20% biodiesel must meet ASTM specification
D7467 (Biodiesel blend, B6 - B20) and are
labeled with an orange or blue label. To
reduce the risk of poor quality fuel,
Driving and Operating
purchase biodiesel blends from a fuel
supplier or fueling station which sells
BQ-9000 certified biodiesel. See
www.bq-9000.org for a list of certified
marketers.

Cold Weather Operation

Diesel fuel is sensitive to temperature. All
diesel fuel has a certain amount of paraffin
components, which are high in energy value
and help improve fuel economy. But, when
temperatures are below -7 °C (20 °F), the
paraffin components begin turning into wax
flakes. If temperatures are low enough,
these flakes can obstruct the fuel filters and
stop fuel from reaching the engine.
At low temperatures, wax flakes are more
likely to form in Number 2-D fuel than in
Number 1-D (or "winterized" Number 2-D)
fuel. For best operation at temperatures
below -7 °C (20 °F), use Number 1-D,
or Number 2-D which has been blended with
Number 1-D for winter use. When
temperatures are consistently below (or
near) -18 °C (0 °F), use Number 1-D if at all
possible. Bear in mind, however, that even
Number 1-D fuel will form wax flakes when
temperatures are extremely low.
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