PLATE AS 2566762 - Caterpillar

Introduction
SCHEMATIC OF THE COOLING SYSTEM (Typical)
1. Cylinder head. 2. Elbow. 3. Radiator cap. 4. Coolant line. 5. Cylinder block. 6. Water pump. 7. Coolant line. 8. Engine oil cooler. 9. Coolant line. 10. Radiator.Water pump (6) is driven from the crankshaft pulley by two V-type belts. The water pump gets coolant from the bottom of radiator (10) and sends it into water passages of cylinder block (5). These passages send coolant around the cylinders to take away the heat of combustion.Some of the coolant in the cylinder block is sent through coolant line (7) into oil cooler (8) to cool the oil for lubrication of the engine. The coolant then goes through line (9) to the inlet side of the water pump. The remainder of the coolant in cylinder block (5) goes up into cylinder head (1).Coolant moves through the cylinder head to a thermostat under elbow (2) at the front of the engine. If the coolant is cold (cool), the thermostat will be closed. The coolant will go through a passage in the front cover to the water pump. If the coolant is warm, the thermostat will open and coolant will go through line (4) and into the top tank of radiator (10). Coolant then goes through the core of the radiator to the bottom tank, where it is again sent through the coolant system.Radiator cap (3) is used to keep the correct pressure in the cooling system. This pressure keeps a constant supply of coolant to the water pump. If this pressure goes too high, a valve in the radiator cap moves (opens) to get a reduction of pressure. When the correct pressure is in the cooling system, the valve in the radiator cap moves down (closed). The thermostat is an important part of the cooling system. If the thermostat is not installed in the system most of the coolant from the cylinder head will go through the passage in the front cover to the water pump. This will cause the engine to get too hot in hot weather. In cold weather the small amount of coolant that does flow to the radiator will be too much. The engine will not get to normal temperature for operation.