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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET1990FORWARD CONTROL 6.2 J, AUTOMATIC, 475/M40REPAIR AND DIAGNOSISHEATING, VENTILATION & A/C (HVAC)GENERAL SERVICINGA/C SYSTEM GENERAL SERVICING
1990 Chevrolet Forward Control 6.2 J, Automatic, 475/M40
A/C System General Servicing
1990 Chevrolet Forward Control 6.2 J, Automatic, 475/M40SECTION A/C System General Servicing
- Safety Precautions - Using R-12 Refrigerant
- Safety Precautions - Using Individual R-12 Cans
- Safety Precautions - Multi-Can Dispensing Valves
- Can Tap Installation
- Sight Glass Indicators
- 1990 Passenger Car Service Valves Location
- 1991 Passenger Car Service Valves Location
- 1990 Truck/Van Service Valves Location
- 1991 Truck/Van Service Valves Location
- Stem-Type Valve Operation
- Back-Seated (Operating) Position
- Mid (Test) Position
- Front-Seated (Off) Position
- SCHRADER-Type Valve Operation
- Special Valve Connectors
- Manifold Gauge Set
- Connecting Gauge Set
- Purging Test Hoses
- Stabilizing A/C System
- Pressure Gauge Readings
- Excessive Moisture Gauge Readings
- Defective Thermostatic Switch Gauge Readings
- MISADJUSTED Thermostatic Switch Gauge Readings
- Defective Clutch Cycling Switch Pressure Gauge Readings
- Low R-12 Charge Gauge Readings
- Very Low R-12 Charge Gauge Readings
- Orifice Tube Plugged Gauge Readings
- Expansion Or "H" Valve Stuck Closed
- Expansion Or "H" Valve Stuck Open Gauge Readings
- Compressor Malfunction Gauge Readings
- Condenser Malfunction Or R-12 Overcharge Gauge Readings
- Orifice Tube Replacement
- Orifice Tube Location & Tool Identification
- Refrigerant Recovery
- Discharging A/C System
- Flushing A/C System
- Charging A/C System
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.