Ram Trucks 2012 3500 - Owner Manual - Manual (Page 530)

FUEL REQUIREMENTS
3.7L and 4.7L Engine
These engines are designed to meet all
emissions regulations and provide excel-
lent fuel economy and performance when
using high quality unleaded “regular”
gasoline having an octane rating of 87. The
use of premium gasoline is not recom-
mended, as it will not provide any benefit over regular
gasoline in these engines.
5.7L Engine
This engine is designed to meet all emis-
sions regulations and provide satisfactory
fuel economy and performance when us-
ing high quality unleaded gasoline having
an octane range of 87 to 89. The manufac-
turer recommends the use of 89 octane for
optimum performance. The use of premium gasoline is
not recommended, as it will not provide any benefit over
regular gasoline in these engines.
Light spark knock at low engine speeds is not harmful to
your engine. However, continued heavy spark knock at
high speeds can cause damage and immediate service is
required. Poor quality gasoline can cause problems such
as hard starting, stalling, and hesitations. If you experi-
ence these symptoms, try another brand of gasoline
before considering service for the vehicle.
Over 40 auto manufacturers worldwide have issued and
endorsed consistent gasoline specifications (the World-
wide Fuel Charter, WWFC) which define fuel properties
necessary to deliver enhanced emissions, performance,
and durability for your vehicle. The manufacturer recom-
mends the use of gasoline that meets the WWFC speci-
fications if they are available.
528 STARTING AND OPERATING