Diesel Engine

DIESEL ENGINE

The cooling system used with the diesel engine provides the extra coolant capacity and extra cooling protection needed for higher GVWR (Gross Vehicle Weight Rating) and GCWR (Gross Combined Weight Rating) vehicles.

This system capacity will not affect warm up or cold weather operating characteristics if the thermostat is operating properly. This is because coolant will be held in the engine until it reaches the thermostat "set" temperature.

Diesel engines, due to their inherent efficiency are slower to warm up than gasoline powered engines, and will operate at lower temperatures when the vehicle is unloaded. Because of this, lower temperature gauge readings for diesel versus gasoline engines may, at times be normal.

Typically, complaints of low engine coolant temperature are observed as low heater output when combined with cool or cold outside temperatures.

To help promote faster engine warm-up, the electric engine block heater must be used with cool or cold outside temperatures. This will help keep the engine coolant warm when the vehicle is parked.

A "Cold Weather Cover" is available from the parts department through the Mopar Accessories product line. This accessory cover is designed to block airflow entering the radiator and engine compartment to promote faster engine warm-up. It attaches to the front of the vehicle at the grill opening. The cover is to be used with cool or cold temperatures only. If used with high outside temperatures, serious engine damage could result. Refer to the literature supplied with the cover for additional information.

For engines equipped with exhaust brakes, this device can be used to aid engine warm-up while the engine is idling.

1. To determine if the thermostat is defective, it must be removed from the vehicle.
2. After the thermostat has been removed, examine the thermostat and inside of thermostat housing for contaminants. If contaminants are found, the thermostat may already be in a "stuck open" position. Flush the cooling system before replacing thermostat.
3. Place the thermostat into a container filled with water.
4. Place the container on a hot plate or other suitable heating device.
5. Place a commercially available radiator thermometer into the water.
6. Apply heat to the water while observing the thermostat and thermometer.
7. The thermostat will begin to open at 85.5 - 89.4°C (186 - 193°F). If the valve starts to move before this temperature is reached, it is opening too early. Replace thermostat. The thermostat should be fully open (valve will stop moving) at 97°C (207°F). If the valve is still moving when the water temperature reaches 97°C (207°F), it is opening too late. Replace thermostat. If the valve refuses to move at any time, replace thermostat.