Idle shutdown, Operating precautions, Avoid overheating the engine – Ram Trucks 2013 Chassis Cab - Diesel Supplement User Manual
Page 55: Avoid low coolant temperature operation, Programmable maximum vehicle speed, Chassis cab only)

Idle Shutdown
This feature can be enabled so that the truck will auto-
matically shutdown when the truck has been idling for a
set period of time when the engine is at operating
temperature. Idle time can be set in 5 minute increments
between 5 and 60 minutes. See your local authorized
dealer to enable this feature.
Programmable Maximum Vehicle Speed
(Chassis Cab Only)
This feature allows the owner to set a maximum vehicle
speed for the vehicle. The 3500 Series maximum vehicle
speed can be set between 40 mph (64 km/h) and 87 mph
(140 km/h). The 4500/5500 Series maximum vehicle
speed can be set between 40 mph (64 km/h) and 85 mph
(136 km/h). See your local authorized dealer to enable
this feature.
NOTE:
DO NOT set the maximum vehicle speed to a
value greater than what the vehicle tires are rated for.
Operating Precautions
Avoid Overheating The Engine
The temperature of the engine coolant (antifreeze) (a
mixture of 50% ethylene-glycol and 50% water) must not
exceed the normal range of the temperature gauge 240°F
(116°C) with a 16 psi (110 kPa) radiator cap.
Usually the engine coolant (antifreeze) temperature indi-
cated during operation will be to the left of center in the
normal range of the gauge.
Avoid Low Coolant Temperature Operation
Continual operation at low engine coolant (antifreeze)
temperature below the normal range on the gauge 140°F
(60°C) can be harmful to the engine. Low engine coolant
(antifreeze) temperature can cause incomplete combus-
tion which allows carbon and varnish to form on piston
rings and injector nozzles. Also, the unburned fuel can
enter the crankcase, diluting the lubricating oil and
causing rapid wear to the engine.
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