OPERATION
GAS ENGINE
The primary purpose of a cooling system is to maintain engine temperature in a range that will provide satisfactory engine performance and emission levels under all expected driving conditions. It also provides hot water (coolant) for heater performance and cooling for automatic transmission oil. It does this by transferring heat from engine metal to coolant, moving this heated coolant to the radiator, and then transferring this heat to the ambient air.
- When the Engine is cold and both the primary and secondary thermostats are closed. The coolant will circulate through the engine, heater system, and the bypass. The cooling system has no flow through the radiator
- As the engine warms up, the primary thermostat will start to open at 82 °C ( 179 °F). Coolant will start to flow through the radiator and the internal transmission cooler. The primary thermostat will fully open at 95 °C (203 °F).
- The secondary thermostat will start to open at 95 °C (203 °F). This will increase the coolant flow through the cylinder block and cylinder head and the radiator. The secondary thermostat will fully open at 110 °C (230 °F).
DIESEL
| 1 - COOLANT RECOVERY PRESSURE CONTAINER |
7 - WATER PUMP |
| 2 - PRESSURE CAP |
8 - THERMOSTAT HOUSING |
| 3 - HEATER CORE |
9 - RADIATOR |
| 4 - AUXILIARY HEATER |
10 - COOLANT DRAIN VALVE |
| 5 - ENGINE |
11 - SERVICE FILL VENT VALVE |
| 6 - OIL COOLER |
The water pump draws coolant from the radiator and delivers it to the engine block. The coolant travels through the engine block into the cylinder head. Coolant exits the engine at the thermostat. If the coolant temperature is less than 87°C (189°F) the thermostat directs all of the coolant back to the water pump. If the coolant temperature is between 87°C (189°F) and 102°C (216°F) the thermostat is in the mix mode and directs the coolant to the radiator and the water pump. If the coolant is greater than 102°C (216°F), the thermostat directs all of the coolant to the radiator.
The thermostat also feeds excess coolant and bleeds air from the system through a hose leading to the coolant reservoir. The reservoir returns coolant to the inlet side of the water pump. A port and hose at the rear of the engine block provides coolant to the heater core. This coolant is returned to the engine at the intake side of the water pump.
The oil cooler receives coolant directly from the engine block. A hose returns this coolant to the inlet side of the water pump.