Workshop Manual

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A–21
The expansion valve regulates the flow rate of the
refrigerant. Accordingly, when a malfunction occurs to
this expansion valve, both discharge and suction
pressure decreases, resulting in insufficient cooling
capacity of the evaporator.
The calibration has been changed to match the
characteristics of HFC-134a.
874R200003
Legend
(1) Expansion Valve
(2) Evaporator Assembly
Evaporator
The evaporator cools and dehumidifies the air before the
air enters the passenger compartment. High-pressure
liquid refrigerant flows through the expansion valve into
the low-pressure area of the evaporator. The heat in the
air passing through the evaporator core is lost to the
cooler surface of the core, thereby cooling the air.
As heat is lost between the air and the evaporator core
surface, moisture in the vehicle condenses on the outside
surface of the evaporator core and is drained off as water.
When the evaporator malfunctions, the trouble will show
up as an inadequate supply of cool air. The cause is
typically a partially plugged core due to dirt, or a
malfunctioning blower motor.
The evaporator core with a laminate louver fin is a
single-sided tank type where only one tank is provided
under the core.
874RY00015
Legend
(1) Evaporator Core
(2) Expansion Valve