Page 176 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

2
160 Automobile mechanical and electrical systems

Figure 2.154 Thermostat with its wax pellet in the hot-coolant area

Figure 2.155 Thermostats

be fi tted towards the top if the thermostat is fi tted on its side. Some manufacturers
fi t the thermostat in a radiator hose. The thermostat may also be fi tted directly into its
own housing and, if so, has to be replaced as a complete assembly.
The various designs and manufacturing materials used for radiators ( Fig. 2.156 )
all consist of a series of small tubes through which the coolant fl ows ( Fig. 2.157 ).
Very thin sheets of metal are used to form a large surface area surrounding the
small tubes. This large surface area makes radiators effi cient heat exchangers for
engine-cooling purposes.
The radiator tubes are fi tted to tanks at each end, and these tanks are fi tted with
connections for the top and bottom or cross-fl ow hoses. The traditional radiator
had the core tubes set vertically and the coolant fl owing downward from the
header tank to the bottom tank ( Fig. 2.158 ). The air space required for expansion
Key fact of the coolant could be either in the header tank or in a separate expansion tank.
However, because of the lower frontal area of most modern cars and light
Cross-fl ow radiators usually have a
remote expansion tank to which the vehicles, a different radiator layout is needed. The cross-fl ow radiator has tubes
pressure cap is fi tted. and thin sheet fi ns forming the core ( Fig. 2.159 ). The core tubes run across the
vehicle and the coolant fl ows from one side to the other. The tanks at each
end of the radiator are joined to the core and have connections for the hoses.