Engine Idling; Stopping The Engine - Jeep Grand Cherokee 2015 Owner's Manual

Engine Idling

Avoid prolonged idling, long periods of idling may be
harmful to your engine because combustion chamber
temperatures can drop so low that the fuel may not burn
completely. Incomplete combustion allows carbon and
varnish to form on piston rings, cylinder head valves,
and injector nozzles. Also, the unburned fuel can enter
the crankcase, diluting the oil and causing rapid wear to
the engine.
Driving Condition
Stop and Go
Stop and Go
Highway Speeds
City Traffic
Highway Speeds
Uphill Grade

Stopping The Engine

After full load operation, idle the engine for a few
minutes before shutting it down. This idle period will
allow the lubricating oil and coolant to carry excess heat
away from the turbocharger.
NOTE: Refer to the following chart for proper engine
shutdown.
Load
Empty
Medium
Medium
Maximum GCWR
Maximum GCWR
Maximum GCWR
Turbocharger Tempera-
ture
Cool
Warm
Hot
STARTING AND OPERATING 41
Idle Time (min.) Before
Engine Shutdown
None
0.5
1.0
1.5
2.0
2.5
4