Cooling System Description

The cooling system maintains engine temperature at an efficient level during all engine operating conditions. When the engine is cold the system cools slowly, or not at all, to allow the engine to warm up quickly.
The cooling system includes the following components:
^ A radiator and coolant recovery sub-system
^ Cooling fans
^ Thermostat and housing
^ Coolant pump
^ Accessory drive belt.
Operation of the cooling system requires proper functioning of all components. Coolant is drawn from the radiator by the coolant pump and circulated through coolant jackets in the engine block, intake manifold, and cylinder head(s), and then directed back to the radiator where it is cooled.
This system directs some coolant though hoses to the heater core, to provide for heating and defrosting. A recovery reservoir is connected to the radiator to recover coolant displaced by expansion from high temperatures and maintain correct coolant level. As the coolant cools and contracts it is drawn back into the radiator by vacuum.


Cooling System Circulation
The coolant pump is belt-driven. Coolant from the radiator outlet (lower right side of the radiator) flows to the coolant pump inlet and is pumped through coolant passages in the cylinder block and into the cavities surrounding the cylinder liners. Coolant flows through holes in the cylinder head gaskets into the cylinder head coolant passages and into the throttle body coolant system. Passages in the intake manifold direct the coolant to the thermostat at the front of the manifold. When the thermostat is closed (cold engine), the coolant is prevented from returning to the radiator and is recirculated for quick engine warm-up.
Once the engine has warmed sufficiently, the thermostat opens and coolant flows to the inlet tank on the top left side of the radiator. It is cooled as it flows across the horizontal core tubes to the outlet tanks on the right side of the radiator, completing the cycle.


Flushing Procedure
Various methods and equipment can be used to flush the cooling system. If special equipment is used (such as a back flusher) follow the manufacturer's instructions. However, always remove the thermostat before flushing the system.