degree of vacuum possible (approximately -88 kPa (- 26 in. Hg) or greater) for 30 minutes, close all valves and
turn off vacuum pump. If the system failsto reach specified vacuum, the refrigerant system likely has a leak that
must be corrected. If the refrigerantsystem maintains specified vacuum for at least 30 minutes, start the vacuum
pump, open the suction and discharge valves. Then allow the system to evacuate an additional 10 minutes.
4. Close all valves. Turn off and disconnect the vacuum pump.
5. Charge the refrigerant system (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM CHARGE).
REFRIGERANT SYSTEM CHARGE
WARNING: Refer to the applicable warnings and cautions for this system before performing the following
operation (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNINGS) and (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAUTIONS). Failure to follow the warnings and cautions could result
in possible personal injury or death.
NOTE: Always refer to the Underhood HVAC Specification Label for the refrigerant fill specification of the
vehicle being serviced.
After all refrigerant system leaks have been repaired and the refrigerantsystem has been evacuated, a refrigerant
charge can be injected into the system. For the proper amount of the refrigerant charge, refer to the Underhood
HVAC Specification Label.
An R-134a refrigerant recovery/recycling/charging station that meets SAE Standard J2210 must be used to charge
the refrigerant system with R-134a refrigerant. Refer to the operating instructions supplied by the equipment man-
ufacturer for proper care and use of this equipment.
CHARGING PROCEDURE
CAUTION: A small amount of refrigerant oil is removed from the A/C system each time the refrigerant sys-
tem is recovered and evacuated. Before charging the A/C system, you MUST replenish any oil lost during
the recovery process. Refer the equipment manufacturer instructions formore information.
1. Evacuate the refrigerant system (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM EVACUATE).
2. A manifold gauge set and an R-134a refrigerant recovery/recycling/charging station that meets SAE standard
J2210 should be connected to the refrigerant system.
3. Measure the proper amount of refrigerant and heat it to 52° C (125° F) withthe charging station. See the oper-
ating instructions supplied by the equipment manufacturer for proper useof this equipment.
4. Open both the suction and discharge valves, then open the charge valve toallow the heated refrigerant to flow
into the system.
5. When the transfer of refrigerant has stopped, close both the suction anddischarge valves.
6. If all of the refrigerant charge did not transfer from the dispensing device, open all of the windows in the vehicle
and set the heating-A/C system controls so that the A/C compressor is engaged and the blower motor is oper-
ating at its lowest speed setting. Run the engine at a steady high idle (about 1400 rpm). If the A/C compressor
does not engage, test the compressor clutch control circuit and repair as required.
7. Open the low-side valve to allow the remaining refrigerant to transfer to the refrigerant system.
WARNING: Take care not to open the discharge (high pressure) valve at this time. Failure to follow this
warning could result in possible personal injury or death.
8. Disconnect the charging station and manifold gauge set from the refrigerant system service ports.
9. Reinstall the caps onto the refrigerant system service ports.
DIAGNOSIS AND TESTING
A/C COMPRESSOR
When investigating an A/C system related noise, you must first know the conditions under which the noise occurs.
These conditions include: weather, vehicle speed, transmission in gear or neutral, engine speed, engine tempera-
ture, and any other special conditions. Noises that develop during A/C operation can often be misleading. For exam-
ple: What sounds like a failed front engine bearing or connecting rod, may be caused by loose bolts, nuts, mounting
brackets or a loose compressor clutch assembly.
Drive belts are speed sensitive. At different engine speeds and dependingupon drive belt tension, drive belts can
develop noises that are mistaken for an A/C compressor noise. Improper drive belt tension can cause a misleading
noise when the compressor clutch is engaged, which may not occur when the compressor clutch is disengaged.
Check the accessory drive belt condition and tension as described in Cooling before beginning this procedure.
1. Select a quiet area for testing. Duplicate the complaint conditions as much as possible. Turn the A/C compressor
On and Off several times to clearly identify the compressor noise. Listen to the A/C compressor while the clutch
is engaged and disengaged. Probe the A/C compressor with an engine stethoscope or a long screwdriver with
the handle held to your ear to better localize the source of the noise.
2. Loosen all of the compressor mounting hardware and retighten. Check thecompressor clutch retainer. Be certain
that the clutch field coil is mounted securely to the A/C compressor, and that the clutch plate and pulley are
properly aligned and have the correct air gap (Refer to 24 - HEATING & AIR CONDITIONING/CONTROLS/
CLUTCH-A/C COMPRESSOR - INSTALLATION).
3. To duplicate high-ambient temperature conditions (high head pressure), restrict the air flow through the A/C con-
denser. Install a manifold gauge set or a scan tool to be certain that the discharge pressure does not exceed
2760 kPa (400 psi).
4. Check the refrigerant system plumbing for incorrect routing, rubbing or interference, which can cause unusual
noises. Also check the refrigerant lines and hoses for kinks or sharp bendsthat will restrict refrigerant flow, which
can cause noises (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - DESCRIPTION - REFRIGER-
ANT LINES).
5. If the noise is from opening and closing of the high pressure relief valve, recover, evacuate and recharge the
refrigerant system (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT SYSTEM RECOVERY), (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE - REFRIGERANT SYSTEM EVACUATE) and (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYSTEM CHARGE). If the high pressure relief
valve still does not seat properly, replace the A/C compressor (Refer to 24- HEATING & AIR CONDITIONING/
PLUMBING/COMPRESSOR-A/C - REMOVAL).
6. If the noise is from liquid refrigerant slugging in the A/C suction line,replace the A/C accumulator (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/ACCUMULATOR-A/C - REMOVAL) and check the refrigerant oil
level and the refrigerant system charge (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/REFRIG-
ERANT OIL - STANDARD PROCEDURE - REFRIGERANT OIL LEVEL) (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING- STANDARD PROCEDURE - REFRIGERANT SYSTEM CHARGE).
7. If a slugging condition still exists after replacing the A/C accumulator, then replace the A/C compressor (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING/COMPRESSOR-A/C - REMOVAL) and repeat Step 1.
REMOVAL
3.7L/4.7L ENGINES
WARNING: Refer to the applicable warnings and cautions for this system before performing the following
operation (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNINGS) and (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAUTIONS). Failure to follow the warnings and cautions could result
in possible personal injury or death.
NOTE: The A/C compressor may be removed and repositioned without disconnecting the refrigerant lines or
discharging the refrigerant system. Discharging is not necessary if servicing the compressor clutch, clutch
coil, engine, engine cylinder head or the generator.
1. Recover the refrigerant from the refrigerant system
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE -
REFRIGERANT SYSTEM RECOVERY).
2. Disconnect and isolate the negative battery cable.
3. Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/BELTS-DRIVE -
REMOVAL).
4. Remove the nuts (4) that secure the A/C suction
line (5) and the A/C discharge line (9) to the A/C
compressor (6).
5. Disconnect the refrigerant lines from the A/C com-
pressor and remove and discard the seals.
6. Install plugs in, or tape over all of the opened
refrigerant line fittings and the compressor ports.
7. Loosen the bolt (5) that secures the bracket (7) to
the accessory mounting bracket (4).
8. Remove the three bolts (1, 6 and 3) that secure the
A/C compressor (2) to the accessory mounting
bracket.
9. Remove the A/C compressor from the engine
compartment.
5.7L ENGINE
WARNING: Refer to the applicable warnings and cautions for this system before performing the following
operation (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNINGS) and (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAUTIONS). Failure to follow the warnings and cautions could result
in possible personal injury or death.
NOTE: The A/C compressor may be removed and repositioned without disconnecting the refrigerant lines or
discharging the refrigerant system. Discharging is not necessary if servicing the compressor clutch, clutch
coil, engine, engine cylinder head or the generator.
1. Recover the refrigerant from the refrigerant system
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE -
REFRIGERANT SYSTEM RECOVERY).
2. Disconnect and isolate the negative battery cable.
3. Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/BELTS-DRIVE -
REMOVAL).
4. Disconnect the wire harness connector from the
clutch field coil connector on top of the A/C com-
pressor (6) and the A/C pressure transducer (8) on
the A/C discharge line (1).
5. Remove the nuts (4 and 7) that secure the A/C dis-
charge line and the A/C suction line (5) to the A/C
compressor.
6. Disconnect the refrigerant lines from the A/C com-
pressor and remove and discard the O-rings and
dual plane seals.
7. Install plugs in, or tape over all of the opened
refrigerant line fittings and the compressor ports.
8. Remove the generator support bracket from the
front of the engine (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - REMOVAL).
9. Remove the three bolts (1 and 3) that secure the
A/C compressor (2) to the mounting bracket (4).
10. Remove the A/C compressor from the engine
compartment.
5.9L DIESEL ENGINE
WARNING: Refer to the applicable warnings and cautions for this system before performing the following
operation (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNINGS) and (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAUTIONS). Failure to follow the warnings and cautions could result
in possible personal injury or death.
NOTE: The A/C compressor may be removed and repositioned without disconnecting the refrigerant lines or
discharging the refrigerant system. Discharging is not necessary if servicing the compressor clutch, clutch
coil or engine.
1. Recover the refrigerant from the refrigerant system
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE -
REFRIGERANT SYSTEM RECOVERY).
2. Disconnect and isolate the negative battery cable.
3. Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/BELTS-DRIVE -
REMOVAL).
4. Remove the bolt (1) that secures the A/C suction
and discharge line assembly (2) to the A/C com-
pressor (3).
5. Disconnect the refrigerant line assembly from the
A/C compressor and remove and discard the seals.
6. Install plugs in, or tape over all of the opened
refrigerant line fittings and compressor ports.
7. Disconnect the wire harness from the clutch field
coil wire lead connector (4).
8. Remove the four bolts (1) that secure the A/C com-
pressor (2) to the mounting bracket (3) located on
the right side of the cylinder block (4).
9. Remove the A/C compressor from the engine
compartment.
8.3L ENGINE
WARNING: Refer to the applicable warnings and cautions for this system before performing the following
operation (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNINGS) and (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAUTIONS). Failure to follow the warnings and cautions could result
in possible personal injury or death.
NOTE: The A/C compressor may be removed and repositioned without disconnecting the refrigerant lines or
discharging the refrigerant system. Discharging is not necessary if servicing the compressor clutch, clutch
coil or the engine.
1. Position the A/C compressor (2) into the engine
compartment.
2. Install and tighten the bolts that secure the A/C
compressor to the mounting bracket (4) in the fol-
lowing sequence:
Install the two lower bolts (1) and hand tighten.
Install the rear bolt (3) and hand tighten.
Tightenthetwolowerboltsto40Nꞏm(30ft.
lbs.).
Tighten the rear bolt to 55 Nꞏm (41 ft. lbs.).
3. Install the generator support bracket (Refer to 8 -
ELECTRICAL/CHARGING/GENERATOR -
INSTALLATION).
4. Remove the tape or plugs from the opened refrig-
erant line fittings and the compressor ports.
5. Lubricate new O-rings and dual plane seals with
clean refrigerant oil and install them onto the refrig-
erant line fittings. Use only the specified seals as
they are made of a special material for the R-134a
system. Use only refrigerant oil of the type recom-
mended for the A/C compressor in the vehicle.
6. Install the A/C discharge line (1) and the A/C suc-
tion line (5) onto the A/C compressor (6).
7. Install the nuts (4 and 7) that secure the refrigerant
lines to the A/C compressor. Tighten the nuts to 20
Nꞏm (15 ft. lbs.).
8. Connect the wire harness connector to the clutch
field coil connector and the A/C pressure trans-
ducer (8).
9. Install the accessory drive belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/BELTS-DRIVE - INSTAL-
LATION).
10. Reconnect the negative battery cable.
11. Evacuate the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYSTEM EVAC-
UATE).
12. Charge the refrigerant system (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM CHARGE).
5.9L DIESEL ENGINE
NOTE: Be certain to check the refrigerant oil level if the A/C compressor isbeing replaced. See Refrigerant
Oil Level in this group for the procedures. Use only refrigerant oil of the type recommended for the A/C
compressor in the vehicle.