Jeep 2013 Grand Cherokee SRT8 Owner's Manual page 550

548 MAINTAINING YOUR VEHICLE
American Petroleum Institute (API) Engine Oil
Identification Symbol
This symbol means that the oil has
been certified by the American
Petroleum Institute (API). The
manufacturer only recommends
API Certified engine oils.
CAUTION!
Do not use chemical flushes in your engine oil as the
chemicals can damage your engine. Such damage is
not covered by the New Vehicle Limited Warranty.
Engine Oil Viscosity
SAE 0W-40 Full Synthetic engine oil is preferred for use
in all operating temperatures.
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 Com-
partment" in "Maintaining Your Vehicle" for further
information.
Synthetic Engine Oils
You may use synthetic engine oils provided the recom-
mended oil quality requirements are met, and the recom-
mended maintenance intervals for oil and filter changes
are followed.
Materials Added To Engine Oil
The manufacturer strongly recommends against the addi-
tion of any additives (other than leak detection dyes) to the