Section III. INTER-RELATION OF COOLING SYSTEM AND OTHER ENGINE SYSTEMS

c. Other Coolant Distributing Devices. Some valve-

in-head engines have small water nozzles or jets built into

the cylinder head to direct the flow of coolant toward

exhaust valve seats. Other systems use built-in plates or

baffles to direct coolant circulation in the water jacket.

1-18.

Shutters, Screens, Etc.

Brush guards, air inlet screens, or similar attachments

may have no direct connection with the cooling system

and may be entirely for protective purposes; however, they

all restrict the flow of air through the radiator and,

therefore, must be considered In connection with engine

cooling. Improperly adjusted shutters or clogged air inlet

screens may reduce air flow so much that cooling capacity

of the system can be seriously affected.

1-19.

Gaskets

When two flat surfaces are bolted together to confine a

liquid under pressure, they are usually sealed with a

gasket In automotive cooling systems, gaskets are used

between flanges which house the thermostat. They are

also used between water pump flanges and in bolt-on type

radiator tanks. See 1-14 Cylinder Head Gasket.

Figure 1-13. Coolant flow through water distribution tube

in engine water jacket.

Section III. INTER-RELATION OF COOLING SYSTEM AND OTHER ENGINE SYSTEMS

operation of the cooling system. If the coolant fails to

1-20.

General

remove its share of waste heat, excessive metal

temperatures may reduce or destroy the lubricating value

Separate circulating systems may be connected to the

of the oil. Excessive heat may also cause chemical

engine cooling system to provide cooling for auxiliary

changes in the oil which produce sludge, "varnish," and

engines and air compressors. In some cases temperature

other harmful deposits. Overcooling also interferes with

regulation for a chassis unit, such as transmission, is

proper lubrication.

provided by circulating engine coolant through the unit.

1-22.

Other Engine Accessory Systems

1-21.

Engine Lubricating System

a. General In a number of ways, the operation of

The cooling system and lubricating system are dependent

the cooling system affects and is affected by the operation

on each other for proper operation. Flow of lubricating oil

of other engine accessory systems.

assists in keeping the engine at proper operating

temperatures by transferring part of the waste heat from

b. Fuel System.

Overcooling wastes fuel and

pistons to cylinder walls and by removing the heat from

overheating may cause vapor lock Conversely, an

bearings. In addition, the oil reduces waste heat from

improper mixture of fuel and air raises the coolant

friction by properly lubricating the moving parts. On the

other hand, satisfactory lubrication depends on proper

1-10