Air Conditioning
Air Conditioning
The A/C refrigerant system is a clutch cycling orifice tube type. The system components include the:
- A/C compressor.
- A/C compressor clutch field coil.
- A/C clutch disc and hub.
- condenser core.
- evaporator core.
- suction accumulator.
- connecting refrigerant lines.
The refrigeration system operation is controlled by the:
- evaporator core orifice.
- A/C cycling switch.
- A/C pressure relief valve.
- pressure cutoff switch.
The refrigerant system incorporates an A/C compressor controlled by the PCM through an A/C clutch relay.
The A/C cycling switch senses evaporator core pressure to control A/C compressor cycling.
An A/C pressure relief valve is installed in the compressor manifold and tube assembly to protect the refrigerant system against excessively high refrigerant pressures.
An evaporator core orifice is installed in the evaporator core inlet tube to meter the liquid refrigerant into the evaporator core.
A/C Compressor and Clutch Assembly
NOTE: Internal A/C compressor components are not serviced separately. The FS-10 A/C compressor is serviced only as an assembly. The A/C clutch disc and hub, A/C clutch pulley, A/C clutch field coil and the shaft seal are serviceable.
NOTE: Installation of a new suction accumulator is not required when repairing the A/C system except when there is physical evidence of contamination from a failed A/C compressor or damage to the suction accumulator.
The FS-10 A/C compressor has the following characteristics:
- A 10-cylinder swashplate design utilizing the tangential design mount.
- A 1-piece lip-type seal (replaceable from the front of the A/C compressor) is used to seal it at the shaft opening in the assembly.
- Five double-acting pistons operate within the cylinder assembly. The pistons are actuated by a swashplate that changes the rotating action of the shaft to a reciprocating force.
- Reed-type discharge valves are located between the cylinder assembly and the head at each end of the A/C compressor.
- The A/C compressor uses PAG oil or equivalent. This oil contains special additives required for the A/C compressor.
- The A/C compressor oil from vehicles equipped with an FS-10 A/C compressor may have a dark color while maintaining a normal oil viscosity. This is normal for the A/C compressor because carbon from the piston rings will discolor the oil.
The magnetic A/C clutch has the following characteristics:
- It drives the compressor shaft.
- When the battery positive voltage (B+) is applied to the A/C compressor 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 compressor clutch field coil, springs in the clutch disc and hub assembly move the clutch disc away from the A/C clutch pulley.
A/C Pressure Relief Valve
NOTE: If the A/C compressor is operating within limits and the A/C pressure relief valve is venting, or if the A/C pressure relief valve is leaking around the threads, replace the A/C pressure relief valve and O-ring. If the A/C pressure relief valve still vents after it is replaced, diagnose the refrigerant system for a restriction.
An A/C pressure relief valve is incorporated in the compressor manifold and tube assembly to:
- relieve unusually high refrigerant system discharge pressure buildups.
- prevent damage to the A/C compressor and other system components.
- avoid total refrigerant loss by closing after the excessive pressure has been relieved.
The A/C pressure relief valve is a separate component and can be replaced separately from the A/C compressor manifold and tube assembly. It is necessary to recover the refrigerant before removing the A/C pressure relief valve.
Condenser Core
The condenser core has the following characteristics:
- It is an aluminum fin and tube design heat exchanger located in front of 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.
Evaporator Core
NOTE: The evaporator core is not separately serviceable. It is serviced only with the evaporator core housing assembly.
NOTE: Installation of a new suction accumulator is not required when repairing the A/C system except when there is physical evidence of system contamination from a failed A/C compressor or damage to the suction accumulator.
The evaporator core is the plate/fin type.
- A mixture of refrigerant and oil enters the bottom of the evaporator core through the evaporator core inlet tube and then moves out of the evaporator core through the evaporator core outlet tube as a vapor.
- All airflow from the blower motor passes through the evaporator core and, during A/C operation, is cooled and dehumidified.
- The evaporator core is located in the evaporator core housing at the RH rear of the engine compartment.
A/C Evaporator Core Orifice
NOTE: A new A/C evaporator core orifice should be installed whenever a new A/C compressor is installed.
The A/C evaporator core orifice has the following characteristics:
- It is located in the evaporator core inlet tube
- It has filter screens located on the inlet and outlet ends of the tube body
- The inlet filter screen acts as a strainer for the liquid refrigerant flowing through the A/C evaporator core orifice
- O-ring seals on the A/C evaporator core orifice prevent the high-pressure liquid refrigerant from bypassing the A/C evaporator core orifice
- The A/C evaporator core orifice assembly cannot be adjusted or serviced. It must be installed as a unit
Suction Accumulator
NOTE: Installation of a new suction accumulator is not required when repairing the A/C system, except when there is physical evidence of contamination from a failed A/C compressor or damage to the suction accumulator. Damage to the suction accumulator includes leaks in the suction accumulator, physical damage to the suction accumulator shell or desiccant, or moisture contamination. Moisture contamination results only from a complete loss of refrigerant, and equalization of the refrigerant system pressure with atmospheric pressure for a period longer than one hour. If even a slight amount of positive refrigerant pressure is present in the refrigerant system before repairs are carried out, the suction accumulator should not be replaced.
After entering the inlet of the suction accumulator, heavier oil-laden refrigerant contacts an internally mounted dome (which serves as an umbrella) and drips down onto the bottom of the canister.
- A small diameter oil bleed hole, in the bottom of the vapor return tube, allows the accumulated heavier liquid refrigerant and oil mixture to re-enter the compressor suction line at a controlled rate.
- As the heavier mixture passes through the small diameter liquid bleed hole, it has a second chance to vaporize and recirculate through the A/C compressor without causing compressor damage due to slugging.
- A fine mesh screened filter fits tightly around the bottom of the vapor return tube to filter out refrigerant system contaminant particles.
- A desiccant bag is mounted inside the canister to absorb any moisture in the refrigerant system.
- A fitting located on the side of the suction accumulator is used to mount a serviceable low-pressure A/C charge port valve.
Refrigerant System Dye
Fluorescent refrigerant system dye is added to the refrigerant system at the factory to assist in refrigerant system leak diagnosis using a Rotunda-approved UV blacklight. It is not necessary to add additional dye to the refrigerant system before diagnosing leaks, even if a significant amount of refrigerant has been removed from the system. Replacement suction accumulators are shipped with a fluorescent dye "wafer" included in the desiccant bag, which will dissolve after approximately 30 minutes of continued A/C operation. It is not necessary to add dye after flushing or filtering the refrigerant system because a new suction accumulator is installed as part of the flushing or filtering procedure. Additional refrigerant system dye should only be added if more than 50% of the refrigerant system lubricant capacity has been lost due to a fitting separation or hose rupture.
A/C Cycling Switch
The A/C cycling switch is mounted on a Schrader valve-type fitting on the top of the suction accumulator.
- A valve depressor, located inside the threaded end of the A/C cycling switch, presses in on the Schrader valve stem.
- This allows the suction pressure inside the suction accumulator to control the operation of the A/C cycling switch.
- The electrical switch contacts open when the suction pressure drops. The contacts close when the suction pressure rises.
- When the A/C cycling switch contacts close, the signal to energize the A/C compressor clutch field coil is sent to the PCM. The PCM will then actuate the A/C clutch relay, energizing the A/C compressor.
- When the A/C cycling switch contacts open, the A/C compressor clutch field coil is de-energized and A/C compressor operation stops.
- The A/C cycling switch will control the evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly above freezing.
- This prevents icing of the evaporator core and blockage of airflow.
- It is not necessary to recover the refrigerant to remove the A/C cycling switch.
High-Pressure Cutoff Switch
The high-pressure cutoff switch is used to interrupt A/C operation in the event of high system discharge pressures.
- The high-pressure cutoff switch is mounted on a Schrader valve-type fitting on the high-pressure side of the compressor manifold and tube assembly (3.0L and 4.0L engines) or the compressor to condenser discharge line (2.3L engine only).
- A valve depressor, located inside the threaded end of the high-pressure cutoff switch, presses on the Schrader valve stem.
- This allows the high-pressure cutoff switch to monitor the compressor discharge pressure.
- When the compressor discharge pressure rises, the switch contacts open, interrupting A/C operation. When the pressure drops, the contacts close.
- It is not necessary to recover the refrigerant to remove the pressure cutoff switch.
Spring Lock Coupling
When disconnecting or connecting spring lock couplings, observe the following.
- 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 2 halves of the couplings.
- Use only the O-ring seals listed in the Ford Master Parts Catalog for the spring lock coupling.
- A plastic indicator ring is used to indicate, during vehicle assembly, that the coupling is connected. Once the coupling is connected, the indicator ring is no longer necessary but will remain captive by the coupling near the cage opening.
- The indicator ring may also be used during service operations to indicate connection of the coupling.
- An A/C tube lock coupling clip is used to secure the coupling and is required.
Peanut Fitting
When disconnecting or connecting peanut fittings, observe the following.
- The male and female blocks of the peanut fitting are retained with a nut.
- Support the female fitting with a wrench to prevent twisting of the tubes.
- An O-ring seal is installed around the tube on the male block.
- When correctly assembled, the male and female fittings should be flush.
- Use only the O-ring seal listed in the Ford Master Parts Catalog.
Tube-O Fitting
When disconnecting or connecting tube-O fittings, observe the following.
- The male and female portions of the fitting are retained with a nut.
- Support the female fitting with a wrench to prevent twisting of the tubes when disconnecting.
- An O-ring seal is installed around the tube on the male side of the fitting.
- Use only the O-ring seal listed in the Ford Master Parts Catalog.
Service Gauge Port Valves
The high-pressure service gauge port valve is located on the compressor-to-condenser discharge line.
The low-pressure service gauge port valve is located on the suction accumulator.
The fitting is an integral part of the refrigeration line or component.
- Special couplings are required for both the high-side and low-side service gauge ports.
- A very small amount of leakage will always be detectable around the Schrader-type valve with the service gauge port valve cap removed, and is considered normal. A new Schrader-type valve core can be installed if the seal leaks excessively.
- The service gauge port valve caps are used as primary seals in the refrigerant system to prevent leakage through the Schrader-type valves from reaching the atmosphere. Always install and tighten the A/C service gauge port valve caps to the correct torque after they are removed.