Dodge 2016 Challenger Owner's Manual page 567

MAINTENANCE SCHEDULES 565
Miles:
Or
6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120 126 132 138 144 150
Months:
Or Kilo-
meters:
Replace
the spark
plugs – X
6.4L En-
gine **
Flush and
replace
the engine
8
coolant at
120
X X
months if
not done
at 150,000
miles
(240,000 km).