Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1990CHEVY VAN G20, 4.3 Z, 475/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)HEATING, VENTILATION & A/C (HVAC)HVAC CONTROL SYSTEMSA/C-HEATER SYSTEM - MANUALREMOVAL & INSTALLATIONEXPANSION VALVE
1990 Chevrolet Chevy Van G20, 4.3 Z, 475/M40
Expansion Valve
1990 Chevrolet Chevy Van G20, 4.3 Z, 475/M40SECTION Expansion Valve
NOTE:
Expansion valve is used on auxiliary units that do not use external equalizer line.
- Disconnect battery ground. Discharge refrigerant system using approved refrigerant recovery/recycling equipment. Remove rear duct. Disconnect blower motor ground and lead wires. Support lower case and motor. Remove screws attaching case halves and lower case and motor assembly. Remove expansion valve sensing bulb clamps. See Fig 1.
- Disconnect valve inlet and outlet lines and remove expansion valve. Cap open connections. To install, reverse removal procedure. Use new "O" rings lubricated with clean refrigerant oil. Ensure bulb makes good contact with core outlet line. Leak test, evacuate and recharge system.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.