Procedure 2 - Ambient Temperature Above 38°C (100°F)

WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: The system performance can be evaluated and diagnosed by analysis of the compressor suction and discharge pressures. The following procedure is used to determine if the system is operating at normal pressures.

NOTE: The procedure varies depending on the ambient (shop) temperature. If the ambient temperature is 38°C (100°F) or lower, follow procedure 1. If the ambient temperature is over 38°C (100°F), follow procedure 2.

Drive the vehicle or run the engine until it reaches normal operating temperature.
Connect a manifold gauge set or refrigerant service center with high-pressure and low-pressure gauges to the refrigerant system.
Set the climate controls.
- If equipped with manual climate control, set the A/C controls for normal A/C-PANEL mode, full COOL temperature, FRESH air, MED LO blower. If the vehicle has a fresh air/recirc button, set it to FRESH. If the vehicle has an A/C switch or compressor on switch, set it to A/C ON.
- If equipped with ATC, set temperature to 60°F (15°C) (lowest possible temp setting). Manually set blower to MED LO (3 to 4 bars). If the vehicle has a fresh air/recirc button, set it to FRESH. If the vehicle has an A/C switch or compressor on switch, set it to A/C ON.
- If the vehicle is equipped with auxiliary climate control, set the auxiliary controls to full COOL in the PANEL mode at MED LO blower speed.
Open all vehicle windows and leave the hood open for the test. Open the rear hatch and/or rear doors (if equipped).
Confirm the compressor clutch is engaged and the engine cooling fan(s) are operating or engaged.
Allow the vehicle to idle until the suction (low-side) and discharge (high-side) pressures are stable or fluctuate in a range that repeats.
Record the ambient (shop) temperature.
Record the discharge pressure. If the pressure is fluctuating, record the average value.
Determine if the discharge pressure falls within the normal operating limits using the Normal Refrigerant Discharge Pressures chart.

Fig 1: Identifying Normal Discharge Pressure Graph
Courtesy of FORD MOTOR CO.
Record the suction pressure. If the pressure is fluctuating, record the average value.
Determine if the suction pressure falls between normal operating limits using the Normal Refrigerant Suction Pressures chart.

Fig 2: Identifying Normal Suction Pressure Graph
Courtesy of FORD MOTOR CO.
Refer to the chart below.