Envoy 2WD V6-4.3L VIN W (1998)
Heater Core: Description and Operation
Temperature Valve and Heater Core
The temperature of the air discharged from the heater system is regulated by controlling the relative amounts of warm and cool air that are mixed
together downstream from the heater core area. The part of the total airflow that is allowed to pass through the heater core is governed by the position of
the temperature valve.
Hot coolant from the engine's cooling system is directed through the heater core. The heater core transfers heat from the coolant to the air passing
through the fins.
