A/C Refrigerant System

Component Locations:

Refrigeration System Components:

The A/C refrigerant system is a clutch cycling, thermostatic expansion valve type. The system components are:
- A/C compressor
- A/C clutch
- A/C condenser core
- A/C evaporator core
- thermostatic expansion valve
- receiver drier
- connecting refrigerant lines

The refrigeration system operation is controlled by the:
- thermostatic expansion valve.
- evaporator discharge temperature sensor.
- A/C compressor pressure relief valve.
- A/C pressure transducer.
- Powertrain Control Module (PCM).
- DATC module.
- ambient temperature sensor.

The refrigerant system incorporates a variable capacity A/C compressor. The A/C compressor clutch engagement is controlled by the vehicle PCM. The evaporator discharge temperature sensor senses evaporator discharge temperature. The DATC module monitors the evaporator discharge temperature sensor and communicates with the PCM to control clutch cycling. The DATC also monitors the ambient air temperature sensor and disables A/C operation when the ambient air temperature is below 0°C (32°F).

The A/C pressure transducer is located in the compressor discharge line and is monitored by the PCM. If high or low refrigerant pressures are experienced, the PCM will interrupt A/C compressor operation.

The pressure relief valve is installed in the compressor manifold and tube assembly and protects the system from excessively high refrigerant pressure.

The thermostatic expansion valve, which is mounted to the evaporator core inlet and outlet tubes, contains an adjustable orifice which provides the restriction that separates the high and low pressure liquid phases in the refrigeration system.







A/C Compressor and Clutch Assembly

NOTE: Internal A/C compressor components are not serviced separately. The A/C scroll compressor is serviced only as an assembly. The A/C clutch, A/C clutch pulley and the A/C clutch field coil are serviceable.

The Ford Variable Scroll A/C compressor (SC90V) has the following characteristics:
- A variable capacity function controlled by a suction pressure sensing device.
- Displacement of 90cc (5.5 cubic inch).
- A fixed and orbiting scroll to provide refrigerant compression.
- A non-serviceable shaft seal.
- The A/C compressor uses PAG Refrigerant Compressor Oil YN-12-C, F7AZ-19589-DA or equivalent meeting Ford specification WSH-M1C231-B. This oil contains special additives necessary for the A/C compressor.

The A/C compressor contains a thermal cutout switch which senses the compressor housing temperature. The switch will disengage the A/C compressor clutch if the housing temperature exceeds 120°C (247°F).

SC90V A/C compressors used on the six and eight cylinder engines are not interchangeable.

Compressor Clutch Components:

The SC90V magnetic A/C clutch has the following characteristics:
- It drives the compressor shaft.
- When battery positive voltage (B+) is applied to the A/C clutch field coil, the clutch disc and hub assembly is drawn toward the A/C clutch pulley.
- The magnetic force locks the clutch disc and hub assembly and the A/C clutch pulley together as one unit, causing the compressor shaft to rotate.
- When B+ is removed from the A/C clutch field coil, springs in the clutch disc and hub assembly move the clutch disc away from the A/C clutch pulley.

A/C Compressor Pressure Relief Valve
An A/C compressor pressure relief valve is incorporated into the compressor A/C manifold and tube to:
- relieve unusually high refrigerant system discharge pressure buildups (3,103 kPa and above).
- prevent damage to the A/C compressor and other system components.
- avoid total refrigerant loss by closing after the excessive pressure has been relieved.







A/C Condenser Core
The A/C condenser core has the following characteristics:
- It is an aluminum fin and tube design heat exchanger located in front of the vehicle radiator.
- It cools compressed refrigerant gas by allowing air to pass over fins and tubes to extract heat and by condensing gas to liquid refrigerant as it is cooled.

Refrigerant Lines
The manifold and tube assembly-receiver drier carries the high pressure liquid from the condenser core to the receiver drier, and from the receiver drier to the manifold and tube assembly-thermostatic expansion valve. It attaches to the A/C receiver drier, uses O-ring seals, and also contains the high pressure service port.

The manifold and tube assembly-thermostatic expansion valve carries high pressure liquid to the thermostatic expansion valve and low pressure gas from the thermostatic expansion valve to the manifold and tube assembly-A/C compressor.

The manifold and tube assembly-A/C compressor carries the high pressure gas from the A/C compressor to the condenser core. It also carries the low pressure gas received from the manifold and tube assembly-thermostatic expansion valve to the A/C compressor. The A/C manifold and tube assembly is attached to the A/C compressor, uses O-ring seals, and has:
- a Schrader-type valve stem core fitting used to mount the A/C pressure transducer so that the A/C pressure transducer can be removed without discharging the A/C system.
- a serviceable high pressure relief valve.

The manifold and tube assembly-A/C compressor used on the V6 and V8 engines are not interchangeable.

A/C Evaporator Core
The A/C evaporator core is the plate/fin type with a unique refrigerant flow path.
- A mixture of refrigerant and oil exits the Thermostatic Expansion Valve (TXV) and enters the evaporator tank area through the 1/2 inch (12.7 mm) tube.
- The tank area is divided into three sections: front inlet, front outlet and rear tank.
- The refrigerant enters the evaporator core tank area at the front inlet, flows down through the core and up the back side in a "U-flow" pattern.
- The refrigerant moves into the rear tank area and across to the other half of the core. The refrigerant moves down through the core and back up the front side of the core to the front outlet tank area.
- The refrigerant at this point is in a gaseous state. It exits the evaporator through the 5/8 inch (15.9 mm) tube then passes through the TXV.

Thermostatic Expansion Valve:

A/C Thermostatic Expansion Valve
The thermostatic expansion valve has the following characteristics:
- It is mounted on the A/C evaporator core inlet and outlet tubes.
- It is a block-type valve.
- It contains an internal sensing bulb to increase the effectiveness of temperature sensing.
- It is not serviceable. A new thermostatic expans!on valve must be installed as a unit.

Receiver Drier
The receiver drier is mounted to the engine fan shroud to the right of the vehicle center. The inlet tube of the receiver drier attaches directly to the A/C condenser core and the outlet tube of the receiver drier attaches to the thermostatic expansion valve inlet line.

The receiver drier stores high pressure liquid after it leaves the condenser core. A desiccant bag mounted in the receiver drier removes any retained moisture.

The manifold and tube assembly that mounts to the top of the receiver drier contains the high pressure service port for the refrigerant system.

A/C Pressure Transducer
The A/C pressure transducer monitors the compressor discharge pressure and communicates with the Powertrain Control Module (PCM). The PCM will interrupt A/C compressor operation in the event that the A/C pressure transducer indicates high system discharge pressures. It is also used to sense no or low charge conditions. If the pressure is below a predetermined value for a given ambient temperature, the PCM will not allow the clutch to engage.
- The A/C pressure transducer is mounted on a Schrader valve-type fitting on the A/C compressor to condenser discharge line.
- A valve depressor, located inside the threaded end of the A/C pressure transducer, presses on the Schrader valve stem and allows the A/C pressure transducer to monitor the compressor discharge pressure.
- When the compressor discharge pressure rises to approximately 2,896 kPa (420 psi), the PCM will interrupt the A/C compressor clutch coil circuit and disengage the A/C compressor.
- When the pressure drops to approximately 1,724 kPa (250 psi), the PCM will enable the A/C compressor circuit.
- It is not necessary to discharge the refrigerant system to remove the A/C pressure cut-off switch.







Spring Lock Coupling
The spring lock coupling is a refrigerant line coupling held together by a garter spring inside a circular cage. The spring lock coupling is used to connect the A/C compressor manifold and tube assembly (inlet) to the TXV manifold and tube assembly (outlet).
- When the coupling is connected together, the flared end of the female fitting slips behind the garter spring inside the cage of the male fitting.
- The garter spring and cage then prevent the flared -end of the female fitting from pulling out of the cage.
- Three O-ring seals are used to seal between the thermostatic expansion valve outlet tube and the compressor inlet tube. All other couplings have two O-ring seals.
- These O-ring seals are green in color and are made of special material.
- Use only the green O-ring seals listed in the Ford Master Parts Catalog for the spring lock coupling.
- An A/C tube lock coupling clip is used to secure the coupling.







Peanut Fitting
The A/C condenser core and the connection between the receiver drier manifold assembly (outlet) and the TXV manifold and tube assembly (inlet) use the peanut-shaped refrigerant fittings instead of spring lock couplings.
- The male and female blocks of the peanut fitting are retained with a nut.
- An O-ring seal is installed around the tube on the male block.
- When correctly assembled, the male and female fittings should be flush.

Service Gauge Port Valves
The high-pressure service gauge port valve is located on the A/C receiver drier manifold and tube assembly.

The low pressure service gauge port valve is located on the manifold of the A/C compressor manifold and tube assembly at the A/C compressor.

Service Gauge Port Values:

The fitting is an integral part of the refrigeration line or component.
- Special couplings are necessary for both the high side and low side service gauge ports.
- A new Schrader-type valve core can be installed if the seal leaks.
- Always install the A/C charging valve cap on the service gauge port valves after repairing the refrigerant system.