Cooling System: Description and Operation

DESCRIPTION-COOLING SYSTEM FLOW 5.9L DIESEL
The diesel engine cooling system consists of:
- Cross-flow radiator
- Belt driven water pump
- Belt driven mechanical cooling fan
- Electronic viscous fan drive
- Fan shroud
- Radiator pressure cap
- Vertically mounted thermostat
- Coolant reserve/recovery system
- Transmission oil cooler
- Coolant





Coolant flow circuits for the 5.9L diesel engine are shown.

OPERATION - COOLING SYSTEM
The cooling system regulates engine operating temperature. It allows the engine to reach normal operating temperature as quickly as possible. It also maintains normal operating temperature and prevents overheating.

The cooling system also provides a means of heating the passenger compartment and cooling the automatic transmission fluid (if equipped). The cooling system is pressurized and uses a centrifugal water pump to circulate coolant throughout the system.

5.9L, 5.9L Diesel, and 8.0L engines utilize an ambient overflow bottle for coolant recovery/reserve. The 3.7L and 4.7L engines utilize a pressurized degas bottle for coolant deaeration and reserve. This degas bottle has coolant flowing through it continuously, supplied by a vent in the hot side radiator tank and returning to the heater return hose.

An optional factory installed maximum duty cooling package is available on most models. This package will provide additional cooling capacity for vehicles used under extreme conditions such as trailer towing in high ambient temperatures.