Ensure ambient temperature is 70-90°F (21-32°C). Place vehicle out of direct sunlight. Place thermometer in center outlet vent. Close windows and doors. Connect manifold gauge set. Place temperature knob at full cold position. Place A/C mode select knob on normal and blower switch in high position.
Operate engine with A/C on, at idle for at least 5 minutes. Check temperature at both sides of orifice tube. If temperature is not same on both sides, go to next step. If temperature is same at both sides, orifice tube is stuck open or missing. Replace orifice tube. Evacuate and charge system. Check system for leaks.
Record high and low side pressures. Check pressure readings with cooling fan on. Pressures should be within correct range. See A/C SYSTEM PERFORMANCE PRESSURE SPECIFICATIONS . Check vent outlet temperature. Outlet vent temperature should be about 20°F (7°C) cooler than ambient temperature.

A/C SYSTEM PERFORMANCE PRESSURE SPECIFICATIONS ⁽¹⁾

High Side: psi (kg/cm² )

Low Side: psi (kg/cm² )

150-200 (10.5-14.1)

32-55 (2.2-3.9)

200-250 (14.1-17.6)

36-59 (2.5-4.1)

250-324 (17.6-22.8)

38-65 (2.1-4.5)

⁽¹⁾	Testing ambient temperature is 70-90°F (21-32°C).

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.

Safety Warning

A/C System Performance