Air Conditioning: Other Jaguar S-type I

A/C Compressor Pressure Relief Valve

An A/C compressor pressure relief valve is incorporated in the compressor A/C manifold and tube to

1. relieve unusually high refrigerant system discharge pressure buildups.
2. prevent damage to the A/C compressor and other system components.
3. avoid total refrigerant loss by closing after the excessive pressure has been relieved.

Scheme 95

The A/C condenser core has the following characteristics

1. It is an aluminum fin and tube design heat exchanger located in front of the vehicle radiator.
2. 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-AC 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, uses O-ring seals, and has

1. 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.
2. a serviceable high pressure relief valve.

The manifold and tube assembly-A/C compressor used on the 3.0L and 4.0L engines are not interchangeable.

A/C Evaporator Core

The A/C evaporator core is the plate/fin type with a unique refrigerant flow path.

Scheme 96

1. A mixture of refrigerant and oil exits the thermostatic expansion valve (TXV) and enters the evaporator tank area through the 12.7 mm (0.5 in) tube.
2. The tank area is divided into three sections: front inlet, front outlet and rear tank.
3. 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.
4. 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.
5. The refrigerant at this point is in a gaseous state. It exits the evaporator through the 16 mm (0.64 in) tube then passes through the TXV.

The thermostatic expansion valve has the following characteristics

1. It is mounted on the A/C evaporator core inlet and outlet tubes.
2. It is a block-type valve.
3. It contains an internal sensing bulb to increase the effectiveness of temperature sensing.
4. It is not serviceable. A new thermostatic expansion 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 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.

1. The A/C pressure transducer is mounted on a Schrader-type valve fitting on the A/C compressor to condenser discharge line.
2. 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.
3. 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.
4. When the pressure drops to approximately 1,724 kPa (250 psi) the PCM will enable the A/C compressor circuit.
5. It is not necessary to discharge the refrigerant system to remove the A/C pressure cut-off switch.
6. Controls the signal to the PCM to control the fan speed.

Scheme 97

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.

1. The male and female blocks of the peanut fitting are retained with a nut.
2. An O-ring seal is installed around the tube on the male block.
3. The female block is welded to the tube and is not adjustable.
4. Support the female fitting with a wrench to prevent the twisting of tubes.
5. The male block will pivot around the tube to allow for alignment with the female block during assembly
6. 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.

Scheme 98

The fitting is an integral part of the refrigerant line or component.

1. Special couplings are necessary for both the high side and low side service gauge ports.
2. A new Schrader-type valve can be installed if the seal leaks
3. Always install the A/C charging valve cap on the service gauge port valves after repairing the refrigerant system.

Evaporator Core

1. Disassemble and assemble the evaporator core housing. For additional information, refer to «EVAPORATOR CORE HOUSING»(ref-199553-S24005842432006082900000) .

Scheme 99

Scheme 100

1. Remove the air intake tube. For additional information, refer to «AIR CLEANER OUTLET PIPE»(ref-199542-S38660142952005101900000) for 3.0L or «AIR CLEANER OUTLET PIPE»(ref-199543-S00056862962005101900000) for 4.0L.
2. Disconnect the pressure cut-off switch electrical connector.
3. Remove the pressure cut-off switch.

Scheme 101

1. To install, reverse the removal procedure.

Scheme 102

Scheme 103

1. Reclaim the refrigerant. For additional information, refer to «AIR CONDITIONING (A/C) SYSTEM RECOVERY, EVACUATION AND CHARGING»(ref-199551-S27055283222005101900000) .
2. Detach the receiver drier supply and return tubes.
3. Remove the receiver drier.

Scheme 104

Scheme 105

1. To install, reverse the removal procedure.