Engine Cooling: Operation: Notes
FLOW DIAGRAM - ENGINE COOLANT
| ITEM | DESCRIPTION |
|---|---|
| 1 | Heater core |
| 2 | Bleed screw |
| 3 | Cylinder head - Bank 1 |
| 4 | Cylinder block |
| 5 | Throttle body |
| 6 | Engine oil cooler |
| 7 | Heater manifold |
| 8 | Cylinder head - Bank 2 |
| 9 | Coolant expansion tank |
| 10 | Automatic Transmission Fluid (ATF) cooler |
| 11 | Electric thermostat |
| 12 | Check valve |
| 13 | Coolant pump |
| 14 | Radiator |
| 15 | Connection with supercharger cooling system |
When the engine is running, the coolant is circulated around the engine cooling system by the coolant pump. The engine coolant flows from the coolant pump through the cylinder heads and the engine oil cooler into the cylinder block and the heater manifold.
In the cylinder block, the coolant flows forward to the outlet tube. When the coolant is cold the electric thermostat is closed, coolant flows direct from the outlet tube back to the coolant pump. When the coolant reaches operating temperature, the thermostat begins to open to control the system temperature, coolant flows from the outlet tube to the coolant pump through the radiator. When the thermostat is open, the coolant flows through the radiator and also generates a coolant flow through the ATF cooler.
From the heater manifold the coolant flows through the throttle body and the heater core, in parallel circuits that are unaffected by the position of the thermostat. From the throttle body, the coolant merges with bleed coolant from the coolant pump and the outlet tube and flows to the expansion tank. From the heater core, the coolant flows back to the inlet of the coolant pump.
Expansion and contraction of the coolant is accommodated by an air space in the expansion tank and the compliance of the flexible hoses.
The supercharger cooling system also uses the engine cooling system for charge air cooling. For additional information, Refer to: SUPERCHARGER COOLING