G 1500 1/2 Ton Van V8-5.7L VIN R (1997)
Thermostat: Description and Operation
Description
A pellet-type thermostat is used in the coolant outlet passage to control the flow of engine coolant, to provide fast engine warm-up and to regulate
coolant temperatures. A pellet element in the thermostat expands when heated and contracts when, cooled. The pellet element is connected through a
piston to a valve. When the pellet element is heated, pressure is exerted against a rubber diaphragm which forces the valve to open. As the pellet
element is cooled, the contraction allows a spring to close the valve. The valve remains closed while the coolant is cold, preventing circulation of
coolant through the radiator. At this point, coolant is allowed to circulate only throughout the engine to warm it quickly.
Operation
As the engine warms, the pellet element expands and the thermostat valve opens, permitting coolant to flow through the radiator, where heat is
dissipated through the radiator tube wails. This opening and closing of the thermostat permits enough coolant to enter the radiator to keep the engine
within operating limits.
