Air Conditioning (A/C) System. Chevrolet Corvette 1997

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1997 🢒 Corvette 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Air Conditioning (A/C) System

The HVAC system delivers air that has been heated or cooled and dehumidified for occupant comfort. The HVAC system also provides the following features:

•	Ventilation

•	Windshield defrosting

•	Side window defogging

During most operating condition, outside air is drawn through the heater and air conditioning module by the blower motor. Additional air is also forced into the vehicle by the forward movement of the vehicle. The blower motor pushes the air through the evaporator core where the air is filtered, dehumidified, and cooled to about 2°C (35°F) when the compressor is ON. Some of the air then passes through the heater core where the flow of hot coolant reheats the air. Depending on the temperature door position, heated air is mixed with cold air from the evaporator before entering into the passenger compartment through the upper, lower, or defroster outlets. This provides positive air flow even with the windows closed.

When the Recirc mode is selected, most of the air entering the evaporator and heater core module is recirculated from the passenger compartment. Recirculated air is most likely cooler and dryer than outside air in very hot weather.

VDOT A/C System


(1)	Compressor
(2)	Condenser
(3)	Evaporator
(4)	Accumulator
(5)	Low Pressure Liquid
(6)	Low Pressure Vapor
(7)	High Pressure Liquid
(8)	High Pressure Vapor
(9)	Expansion (Orifice) Tube
(10)	Liquid Line
(11)	Pressure Relief Valve

The variable displacement orifice tube (VDOT) refrigeration system has a V7 compressor that can maintain the A/C demand under all conditions without cycling. The basic compressor mechanism is a variable angle wobble-plate with axially oriented cylinders. The control of the compressor displacement is a bellows actuated control valve located on the rear head of the compressor. The control valve senses suction pressure. The crankcase to suction pressure differential controls both the wobble-plate angle and the compressor displacement. When the A/C capacity demand is high, the suction pressure will be above the control point. The control valve will maintain a bleed from crankcase to suction. A low crankcase-suction pressure differential gives the compressor maximum displacement. When the A/C demand is lower and the suction pressure reaches the control point, the valve will bleed discharge gas into the crankcase and close off a passage from the crankcase to the suction plenum. A force balance on the pistons controls the angle of the wobble-plate. A slight increase in the crankcase-suction pressure differential creates a force on the pistons, resulting in a movement about the wobble-plate pivot pin that reduces the plate angle.

The compressor has a unique lubrication system. The crankcase-suction bleed is routed through the rotating wobble-plate for lubrication of the wobble-plate bearing. The rotation acts as an oil separator, removing some of the oil from the crankcase-suction bleed, and then reroutes the oil to the crankcase where the oil lubricates the compressor mechanism.

Depending on engine usage, the compressor is cut off. Following are some examples of conditions resulting in compressor cutoff:

•	Wide open throttle

•	Low idle speed

•	Low air temperature

•	High P/S loads

When the engine is turned to OFF with the A/C system running, the refrigerant in the system will flow from the high pressure side of the evaporator tube orifice to the low pressure side until the pressure is equalized. This may be detected as a hissing sound for 30-60 seconds and is a normal condition.