low oil pressure FORD MUSTANG 2003 Repair Manual

to plot a vertical line for ambient temperature and a
horizontal line for A/C clutch OFF time in seconds.
z Is the intersection of the two lines above the upper
limit? DISCHARGE and RECOVER
the system to remove
excessive moisture or
refrigerant oil. REFER to
Air Conditioning (A/C) System
Recovery, Evacuation and
Charging . TEST the system
for normal operation.
No
GO to E7 .
E6 CHECK FOR A HIGH SUCTION PRESSURE
z
Refer to the data plot used to evaluate the system low
pressure performance in Step E3.
z Is the intersection of the two lines above the upper
limit? Yes
REMOVE the A/C evaporator
core orifice to repair missing or
damaged (leaking) O-
ring
seals. REFER to Section 412 -
03 . TEST the system for
normal operation.
No
INSTALL a new A/C cycling
switch when the intersection of
the two lines is below the
lower limit. REFER to Section 412 - 03 . TEST the system for
normal operation. E7 CHECK THE AMBIENT TEMPERATURE
z
Refer to the data plot used to evaluate the system A/C
clutch OFF time in Step E5.
z Is the ambient temperature above 26°C (80°F)? Yes
This is normal operation for
the refrigerant system in high
humidity conditions.
No
DISCHARGE and RECOVER
the system to correct an
overcharge condition. REFER
to
Air Conditioning (A/C) System Recovery, Evacuation
and Charging . TEST the
system for normal operation. E8 CHECK FOR A HIGH DISCHARGE PRESSURE
z
Refer to the data plot used to evaluate the system high
pressure performance in Step E2.
z Is the intersection of the two lines above the upper
limit? Yes
GO to
E9 .
No
GO to E11 .
E9 CHECK FOR A NORMAL LOW PRESSURE
z
Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for compressor suction (low) pressure. Yes
REFER to
Section 303 - 03A or
Section 303 - 03B . to diagnose
the engine cooling system.
TEST the system for normal
operation. Klj . 27 ba
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A/C Evaporator/Condenser Core—
On-Vehicle Leak Test
1. Discharge and recover the refrigerant. For additional information, refer to Air Conditioning (A/C) System Recovery, Evacuation and Charging in this section.
2. NOTE: DO NOT leak test an A/C evaporator core with the suction accumulator/drier (19C836)
attached to the core tubes.
Disconnect the suspect A/C evaporator core or A/C condenser core from the A/C system. For
additional information, refer to Section 412 - 03 .
3. Clean the spring lock couplings. For additional information, refer to Spring Lock Coupling in this
section.
4. Connect the appropriate test fittings from the A/C Test Fitting Set to the evaporator or condenser tube connections.
5. NOTE: The automatic shut- off valves on some gauge set hoses do not open when connected to
the test fittings. If available, use hoses without shut- off valves. If hoses with shut-off valves are
used, make sure the valve opens when attached to the test fittings or install an adapter which
will activate the valve. The test is not valid if the shut- off valve does not open.
Connect the red and blue hoses from the manifold gauge set to the test fittings on the A/C
evaporator core or A/C condenser core. Connect the yellow hose to a known good vacuum
pump.
6. Open both gauge set valves and start the vacuum pump. Allow the vacuum pump to operate for a minimum of 45 minutes after the gauge set low pressure gauge indicates 101 kPa (30 in- Hg).
The 45- minute evacuation is necessary to remove any refrigerant from oil left in the A/C
evaporator core or A/C condenser core. If the refrigerant is not completely removed from the oil,
outgassing will degrade the vacuum and appear as a refrigerant leak.
7. If the low pressure gauge reading will not drop to 101 kPa (30 in- Hg) when the valves on the
gauge and manifold set are open and the vacuum pump is operating, close the gauge set
valves and observe the low pressure gauge. If the pressure rises rapidly to zero, a large leak is
indicated. Recheck the test fitting connections and gauge set connections before installing a
new A/C evaporator core or A/C condenser core.
8. After evacuating for 45 minutes, close the gauge set valves and stop the vacuum pump. Observe the low pressure gauge; it should remain at the 101 kPa (30 in- Hg) mark.
z If the low pressure gauge reading rises 34 or more kPa (10 or more in- Hg) of vacuum
from the 101 kPa (30 in- Hg) position in 10 minutes, a leak is indicated.
z If a very small leak is suspected, wait 30 minutes and observe the vacuum gauge.
z If a small amount of vacuum is lost, operate the vacuum pump with gauge valves open
for an additional 30 minutes to remove any remaining refrigerant from the oil in the A/C Klj . 39 ba
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evaporator core or A/C condenser core. Then recheck for loss of vacuum.
z If a very small leak is suspected, allow the system to sit overnight with vacuum applied
and check for vacuum loss.
9. If the A/C evaporator core or A/C condenser core does leak, as verified by the above procedure, install a new A/C evaporator core or A/C condenser core. For additional information, refer to
Section 412 - 03 .
A/C Compressor— External Leak Test
1. Install the A/C pressure test adapter on the rear head of the A/C compressor using the existing manifold retaining bolt.
2. Connect the high and low pressure lines of a manifold gauge set or a refrigerant recovery/recycling station such as the R- 134a A/C Service Center to the corresponding fittings
on the A/C pressure test adapter.
3. Attach the center hose of the manifold gauge set to a refrigerant container standing in an upright position.
4. Hand- rotate the compressor shaft 10 complete revolutions to distribute the oil inside the A/C
compressor.
5. Open the low pressure gauge valve, the high pressure gauge valve and the valve on the refrigerant container to allow the refrigerant vapor to flow into the A/C compressor.
6. Using the Refrigerant Leak Detector, check for leaks at the compressor shaft seal and the compressor center seal.
7. If a shaft seal leak is found, install a new shaft seal. For additional information, refer to Section 412 - 03 . If an external leak is found at the center joint of the A/C compressor, install a new A/C
compressor.
8. When the leak test is complete, recover the refrigerant. For additional information, refer to Air Conditioning (A/C) System Recovery, Evacuation and Charging in this section. Klj . 40 ba
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Connect an R-
134a A/C service center to the low- and high-pressure service gauge port valves.
3. Recover the refrigerant from the system following the operating instructions provided by the equipment manufacturer.
4. Once the service center has recovered the vehicle A/C system refrigerant, close the service center inlet valve (if equipped). Then switch off the power supply.
5. Allow the vehicle A/C system to remain closed for about two minutes. Observe the system vacuum level as shown on the gauge. If the vacuum does not decrease, disconnect the
refrigerant center hose(s).
6. If the system vacuum does decrease, repeat Steps 2 through 5 until the vacuum level remains stable for two minutes.
7. Carry out the required repairs.
Refrigerant System Evacuation
NOTE: Ford Motor Company recommends use of an A/C service center to carry out recovery,
evacuation, and charging of the refrigerant system. If an A/C service center is not available, refrigerant
system recovery, evacuation, and charging may be accomplished using a separate recovery station,
vacuum pump, charging cylinder, and manifold gauge set.
1. Connect an R- 134a service center to the low- and high-pressure service gauge port valves.
2. Evacuate the system until the low- pressure gauge reads at least 99.4 kPa (29.5 in- Hg) of
vacuum and as close to 101.1 kPa (30 in- Hg) as possible. Continue to operate the vacuum
pump for a minimum of 45 minutes.
3. Turn off the vacuum pump. Observe the low- pressure gauge for five minutes to make sure that
the system vacuum is held. If vacuum is not held for five minutes, leak test the system, service
the leak, and evacuate the system again.
Refrigerant System Charging
NOTE: Ford Motor Company recommends use of an A/C service center to carry out recovery,
evacuation, and charging of the refrigerant system. If an A/C service center is not available, refrigerant
system recovery, evacuation, and charging may be accomplished using a separate recovery station,
vacuum pump, charging cylinder, and manifold gauge set.
1. Correctly oil match the system to verify that the correct amount of refrigerant oil is present in the system. For additional information, refer to Refrigerant Oil Adding in this section.
2. Charge the system with the specified amounts of refrigerant oil and refrigerant.
3. When no more refrigerant is being drawn into the system, start the engine and select MAX A/C operation. Adjust the blower motor speed to the maximum and allow the remaining refrigerant to
be drawn into the system. Continue to add refrigerant into the system until the specified weight
of R- 134a has been added. Close the charging cylinder valve and allow the system to pull any
remaining refrigerant from the hose. When the low- pressure drops to approximately 207 kPa
(30 psi), close the charging hose valve. Klj . 2 ba
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GENERAL PROCEDURES
Refrigerant Oil Adding
CAUTION: During normal A/C operation, oil is circulated through the system with the
refrigerant, and a small amount is retained in each component. If certain components of the
system are removed for new installation, some of the refrigerant oil will go with the component.
To maintain the original total oil charge, it is necessary to compensate for the oil lost by adding
oil to the system with the new part.
1. NOTE: Service A/C compressors are shipped without compressor oil.
Rotate the A/C compressor shaft six to eight revolutions while collecting oil in a clean measuring
device. zIf the amount of oil drained from the old A/C compressor is between 85- 142 ml (3-5
ounces), pour the same amount plus 30 ml (1 ounce) of clean PAG Refrigerant
Compressor Oil (R-134a Systems) F7AZ-19589- DA (Motorcraft YN-12-C) WSH M1C231-
B or equivalent into the new A/C compressor.
z If the amount of oil that was removed from the old A/C compressor is greater than 142 ml
(5 ounces), pour the same amount drained of clean PAG Refrigerant Compressor Oil (R-
134a Systems) or equivalent into the new A/C compressor.
z If the amount of oil that was removed from the old A/C compressor is less than 85 ml (3
ounces), pour 85 ml (3 ounces) of clean PAG Refrigerant Compressor Oil (R- 134a
Systems) or equivalent into the new A/C compressor.
2. For the suction accumulator/drier, drill one 13 mm (0.52 in) hole in the suction accumulator/drier cylinder and drain the oil into a calibrated container.
zAdd a quantity of new oil to match that drained from the old suction accumulator/drier
plus 60 ml (2 ounces) of clean PAG Refrigerant Compressor Oil (R- 134a Systems) or
equivalent.
3. For the A/C evaporator core, add 89 ml (3 ounces) of clean PAG Refrigerant Compressor Oil (R-134a Systems) or equivalent to the suction accumulator/drier inlet tube.
4. For the A/C condenser core, add 30 ml (1 ounce) of clean PAG Refrigerant Compressor Oil (R- 134a Systems) or equivalent to the A/C condenser core or the suction accumulator/drier inlet
tube.
5. Add 60 ml (2 ounces) of clean PAG Refrigerant Compressor Oil (R- 134a Systems) or equivalent
to the suction accumulator/drier inlet tube when carrying out each of the following repairs:
zinstallation of a new A/C evaporator core orifice
z installation of a new A/C compressor pressure relief valve (19D644)
z installation of a new refrigerant line
z repair of an O- ring seal leak
z repair of a charge port leak
6. Installation of new components that do not require discharge of refrigerant and resulting oil loss, such as the A/C cycling switch and the A/C pressure transducer, do not require additional oil.
SECTION 412-
00: Climate Control System - General Information 2003 Mustang Workshop Manual Klj . 1 ba
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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 pulley, A/C clutch field coil (19D798) and the shaft
seal are serviceable.
The FS- 10 A/C compressor has the following characteristics:
z A ten- cylinder swashplate design utilizing the tangential design mount. Item Part Number Description
1 19E561 A/C cycling switch
2 19D701 A/C charge port valve (low side)
3 19D594 Refrigerant containment switch (3.8L vehicles)
3 19D594 Dual-
function pressure switch (4.6L vehicles) 4 19D734 A/C manifold and tube
5 19D644 A/C compressor pressure relief valve
6 19703 A/C compressor
7 19D701 A/C charge port valve (high side)
8 19712 A/C condenser core
9 19835 Condenser to evaporator tube
10 19C836 Suction accumulator
11 — A/C evaporator core (part of 19850 assembly) Klj . 2 ba
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z
A one- piece lip- type seal (installed from the front of the A/C compressor) is used to seal it at the
shaft opening in the assembly.
z Five double- acting pistons operate within the cylinder assembly. The pistons are actuated by a
swashplate that converts the rotating action of the shaft to a reciprocating force.
z Reed- type discharge valves are located between the cylinder assembly and the head at each
end of the A/C compressor.
z The A/C compressor uses PAG oil, or equivalent. This oil contains special additives required for
the A/C compressor.
z The A/C compressor oil from vehicles equipped with an FS- 10 A/C compressor may have some
dark colored streaking while maintaining a normal oil viscosity. This is normal for the A/C
compressor and is caused by break- in wear of the piston rings.
The magnetic A/C clutch has the following characteristics: zIt drives the compressor shaft.
z When the battery positive voltage (B+) is applied to the A/C clutch field coil, the clutch plate and
hub assembly is drawn toward the A/C clutch pulley.
z The magnetic force locks the clutch plate and hub assembly and the A/C clutch pulley together
as one unit, causing the compressor shaft to rotate.
z When (B+) is removed from the A/C clutch field coil, springs in the clutch plate and hub
assembly move the clutch plate away from the A/C clutch pulley. A/C Compressor Pressure Relief Valve Item Part Number Description
1 19D798 A/C clutch field coil
2 19D784 A/C clutch pulley
3 N805338-S2 Pulley snap ring
4 19D648 A/C clutch hub spacer
5 19D786 Disk and hub assembly
6 N805332-S2 A/C clutch bolt Klj . 3 ba
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A/C 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 air conditioning
system except when there is physical evidence of contamination from a failed A/C compressor or
damage to the suction accumulator.
The A/C evaporator core is the plate/fin type with a unique refrigerant flow path.
zA mixture of refrigerant and oil enters the bottom of the A/C evaporator core through the A/C
evaporator core inlet tube and moves out of the A/C evaporator core through the A/C
evaporator core outlet tube.
z This flow pattern accelerates the flow of refrigerant and oil through the A/C evaporator core.
Evaporator Core Orifice
NOTE: The evaporator core orifice is an integral part of the condenser to evaporator line and should
be installed as an assembly with the line.
NOTE: A new evaporator core orifice should be installed whenever a new A/C compressor is installed.
The evaporator core orifice has the following characteristics:
zIt is located in the A/C condenser to evaporator line.
z It has filter screens located on the inlet and outlet ends of the tube body.
z The inlet filter screen acts as a strainer for the liquid refrigerant flowing through the evaporator
core orifice.
z O-ring seals on the evaporator core orifice prevent the high- pressure liquid refrigerant from
bypassing the evaporator core orifice. Klj . 5 ba
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z
Adjustment or repair cannot be made to the evaporator core orifice assembly. A new evaporator
core orifice must be installed as a unit.
Suction Accumulator
NOTE: Installation of a new suction accumulator is not required when repairing the air conditioning
system except when there is physical evidence of contamination from a failed A/C compressor or
damage to the suction accumulator.
In addition to the preceding condition, a new suction accumulator should be installed if one of the
following conditions exist:
zThe suction accumulator is perforated.
z The refrigerant system has been opened to the atmosphere for a period of time longer than
required to make a minor repair.
z There is evidence of moisture in the system such as internal corrosion of metal refrigerant lines
or the refrigerant oil is thick and dark. Item Part Number Description
1 19E561 A/C cycling switch
2 — O-
ring seal (part of 19C836) 3 19D701 Low pressure service gauge port valve
4 — Inlet from A/C evaporator core (part of 19C836)
5 — Outlet to A/C compressor (part of 19C836)
6 — Anti-
siphon hole (part of 19C836) 7 — Desiccant bag (part of 19C836)
8 — Oil return orifice filter (part of 19C836)
9 — Vapor return tube (part of 19C836)
10 — Suction accumulator dome (part of 19C836) Klj . 6 ba
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The suction accumulator (19C836) is mounted to the A/C accumulator bracket (19D606) to the right of
the vehicle centerline. The inlet tube of the suction accumulator attaches directly to the A/C evaporator
core outlet tube and the outlet tube attaches to the A/C manifold and tube.
After entering the inlet of the suction accumulator, the heavier oil-
laden refrigerant contacts an
internally mounted dome (which serves as an umbrella) and drips down onto the bottom of the
canister.
zA small diameter oil bleed hole, in the bottom of the vapor return tube, allows the accumulated
heavier liquid refrigerant and oil mixture to reenter the compressor suction line at a controlled
rate.
z 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.
z A fine mesh screened filter fits tightly around the bottom of the vapor return tube to filter out
refrigerant system contaminant particles.
z A desiccant bag is mounted inside the canister to absorb any moisture which may be in the
refrigerant system.
z A fitting located on the top of the suction accumulator is used to attach the A/C cycling switch. A
long- travel Schrader- type valve stem core is installed in the fitting so that the A/C cycling switch
can be removed without discharging the A/C system.
A/C Cycling Switch
The A/C cycling switch is mounted on a Schrader- type valve fitting on the top of the suction
accumulator.
zA valve depressor, located inside the threaded end of the A/C cycling switch, presses in on the
Schrader valve stem.
z This allows the suction pressure inside the suction accumulator to control the operation of the
A/C cycling switch.
z The electrical switch contacts open when the suction pressure drops. The contacts close when
the suction pressure rises. For specifications regarding operating pressure(s), refer to Section 412 - 00 .
z The A/C cycling switch will control the A/C evaporator core pressure at a point where the
plate/fin surface temperature will be maintained slightly above freezing.
z This prevents icing of the A/C evaporator core and blockage of air flow.
z It is not necessary to discharge the refrigerant system to remove the A/C cycling switch.
Dual- Function Pressure Switch (4.6L)
The dual- function pressure switch is used to interrupt A/C compressor operation in the event of high Klj . 7 ba
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