Ram Trucks 2015 Chassis Cab Commercial - Diesel Supplement - Manual (Page 289)

Engine oil not designated by the Chrysler or Cummins®
Material Standards and API CJ-4 should not be used,
as engine and exhaust system durability may be com-
promised. The engine oil filler cap also shows the
recommended engine oil viscosity for your engine. For
information on engine oil filler cap location, refer to
“Engine Compartment” in “Maintaining Your Vehicle”
for further information.
Synthetic Engine Oils
You may use synthetic engine oils if the recommended oil
quality requirements are met and the recommended
maintenance intervals for oil and filter changes are
followed.
Materials Added To Engine Oil
The manufacturer strongly recommends against the ad-
dition of any additives (other than leak detection dyes) to
the engine oil. Engine oil is an engineered product and its
performance may be impaired by supplemental addi-
tives.
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MAINTAINING YOUR VEHICLE 287