Coolant Flow Schematic Diagram
| ITEM | DESCRIPTION |
|---|---|
| 1 | Engine |
| 2 | Turbocharger |
| 3 | Water outlet |
| 4 | Degas tank |
| 5 | Heater core |
| 6 | Engine oil cooler |
| 7 | By-pass circuit |
| 8 | Radiator |
| 9 | Transmission fluid cooler |
| 10 | Venturi |
| 11 | Thermostat |
| 12 | Water pump |
When the thermostat is fully open, the by-pass circuit is closed and allows maximum coolant flow through the radiator system to provide maximum engine cooling. From the water outlet the majority of the coolant is passed through the radiator and the transmission fluid cooler to the water pump, with a proportion still passing through the turbocharger, heater core and engine oil cooler.
When the thermostat is open the coolant flow from the radiator bottom hose passes through a venturi. This venturi creates a depression which pulls coolant through the transmission fluid cooler. The upper section of the radiator provides low temperature cooling of the engine coolant for the transmission fluid cooler. In hot climates an additional transmission fluid to air cooler is located in front of the radiator and A/C (air conditioning) condenser.
The degas tank accommodates expansion of coolant due to temperature changes and provides a secondary function to extract air from the coolant. A small proportion of the coolant flow is diverted to the degas tank via the bleed line connected to the right radiator end tank. This provides a continuous degas function, independent to the thermostat position.