The cooling system consists of the following major components:
• | Coolant recovery reservoir |
• | Engine coolant air bleed pipe |
• | Engine coolant temperature (ECT) sensor |
• | Transmission oil cooler |
The cooling systems functions is to maintain an efficient engine operating
temperature during all speeds and under all operating conditions. Cooling
systems are designed to remove about one-third (30 to 35 percent) of the
heat produced in the combustion chambers by the burning of the air-fuel mixture.
The engine is very inefficient while cold. Therefore the cooling system includes
a devise (thermostat) that prevents normal cooling action during engine warm-up.
The thermostat allows the engine parts to reach their normal operating temperature
more quickly. This shortens the inefficient cold-operating time. When the
engine reaches its normal operating temperature, the cooling system begins
to function. The cooling system removes excess heat when the engine is hot,
and slowly or not at all when the engine is cold or warming up.
The coolant absorbs heat as it passes through the engine. Then the hot
coolant flows through a radiator in which the heat in the coolant is passed
on to the air that is flowing through the radiator. The cooled coolant then
flows back through the engine. This circulation of the coolant continually
removes heat from the engine. The coolant is kept in circulation by the water
pump.
Water jackets are designed to keep the cylinder block and cylinder heads
cool. The water jackets are open spaces between the outside wall of the cylinder
and the inside of the cylinder block and head. The coolant can circulate
freely around the engine hot spots. These hot spots include the following:
• | Upper parts of the cylinder walls |
When the engine is running at the normal operating temperature, coolant
flows into the block and through the water jackets surrounding the cylinders.
Vapor is vented off through the engine coolant air bleed pipe. Then coolant
is forced through the head gasket openings and into the cylinder head water
jackets. In the heads, the coolant flows around the combustion chambers and
valve seat, picking up additional heat. From the heads, the coolant flows
through the upper hose into the radiator. There, the coolant temperature
is lowered, and the coolant is drawn again into the engine by the water pump
to provide passenger compartment heat and defrost. The coolant recovery reservoir
provides a coolant fill point. The reservoir is translucent for coolant level
viewing.