Heating, Ventilation and Air Conditioning: Other GMC Acadia I

Fluorescent Leak Detector

Fluorescent dye will assist in locating any leaks in the A/C system.

1. Condensation on the evaporator core or the refrigerant lines may wash the PAG oil and fluorescent dye away from the actual leak. Condensation may also carry dye through the HVAC module drain.
2. Leaks in the A/C system will be indicated in a light green or yellow color when using the leak detection lamp. Use the leak detection lamp in the following areas: All fittings or connections that use seal washers or O-rings All of the A/C components The A/C compressor shaft seal The A/C hoses and pressure switches The HVAC module drain tube, if the evaporator core is suspected of leaking The service port sealing caps The sealing cap is the primary seal for the service ports.
3. Follow the instructions supplied with the J 42220 . See «Special Tools»(ref-365250-S10056360502010070600000) .
4. To prevent false diagnosis in the future, thoroughly clean the residual dye from any area where leaks were found. Use a rag and the approved J 43872 . See «Special Tools»(ref-365250-S10056360502010070600000) .

Fluorescent Dye Injection

1. Not all of the fluorescent dyes are compatible with PAG oil. Some types of dye decrease the oil viscosity or may chemically react with the oil.
2. R-134A leak detection dye requires time to work. Depending upon the leak rate, a leak may not become visible for between 15 minutes and 7 days.
3. To prevent false diagnosis, thoroughly clean any residual dye from the service port with a rag and the approved fluorescent dye cleaner J 43872 . See «Special Tools»(ref-365250-S10056360502010070600000) .

Halogen Leak Detector

Ensure that the vehicle has at least 0.45 kg (1 lb) of refrigerant in the A/C refrigeration system in order to perform a leak test. Refer to Refrigerant Recovery and Recharging for recharging the A/C system.

Note. Halogen leak detectors are sensitive to the following items: Windshield washing solutions Many solvents and cleaners Some adhesives used in the vehicle

Clean and dry all surfaces in order to prevent a false warning. Liquids will damage the detector.

Note. Follow a continuous path in order to ensure that you will not miss any possible leaks. Test all areas of the system for leaks.

Follow the instructions supplied with the J 39400-A . See Special Tools .

Defrosting Insufficient

Eliminating Air Conditioning Odor

Odors may be emitted from the air conditioning system primarily at start up in hot, humid climates. The following conditions may cause the odor

1. Debris is present in the HVAC module.
2. Microbial growth on the evaporator core

When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odor into the passenger compartment. To remove odors of this type, the mirocbial growth must be eliminated. Perform the following procedure

Deodorize the evaporator core using Deodorizing Aerosol Kit.

Perform the following steps in order to deodorize the A/C system

1. Ensure that the plenum that draws outside air into the HVAC module is clear of debris.
2. Disable the A/C compressor clutch operation by disconnecting the clutch coil electrical connector.
3. Dry the evaporator core by performing the following steps: Start the engine. Select the maximum temperature setting. Select the recirculation mode. Run the blower motor on high for 10 minutes.
4. Locate an area in the air conditioning duct between the blower motor and the evaporator core downstream of the blower motor.
5. Drill a 3.175 mm (0.125 in) hole where the hole will not interfere with or damage the following components: The blower motor The evaporator core Any other operating part the of system
6. Wear safety goggles and latex gloves in order to perform the following actions: Select the maximum blower speed. Insert the deodorizer extension tube into the hole to the mark on the extension tube. Use short spray bursts and vary the direction of spray for a 2-3 minute period of time.
7. Shut the engine OFF. Allow the vehicle to sit for 3-5 minutes.
8. Seal the 3.175 mm (0.125 in) hole with body sealer or RTV gasket compound.
9. Start the engine.
10. Operate the blower motor on high for 15-20 minutes to dry.
11. Reconnect the A/C compressor clutch coil electrical connector.
12. Verify proper clutch operation.

A/C Refrigerant System Oil Charge Replenishing

If oil was removed from the A/C system during the recovery process or due to component replacement, the oil must be replenished. Oil can be injected into a charged system using J 45037 . See Special Tools . For the proper quantities of oil to add to the A/C refrigerant system, refer to Refrigerant System Capacities .

Tools Required

1. J 43600 ACR 2000 Air Conditioning Service Center. See «Special Tools»(ref-365250-S10056360502010070600000) .
2. J 45268 A/C Flushing Adapter Kit. See «Special Tools»(ref-365250-S10056360502010070600000) .
3. J 41447 Leak Detection Dye. See «Special Tools»(ref-365250-S10056360502010070600000) .
4. J 42220 R-134A A/C Tracer Dye - Box of 24. See «Special Tools»(ref-365250-S10056360502010070600000) .

Flushing is intended to remove the following contaminants

Balancing Procedure

1. The replacement compressor is shipped with 74 ml (2.5 oz) of refrigerant oil.
2. Compare the amount of refrigerant oil recorded during compressor removal to the amount of refrigerant oil shipped in the replacement compressor. If the amount of refrigerant oil drained and recorded from the removed compressor is: Less than 74 ml (2.5 oz) Leave the 74 ml (2.5 oz) in the replacement compressor. More than 74 ml (2.5 oz) Add to the compressor the difference between the 74 ml (2.5 oz) and the amount drained.

Scheme 58

J 39400-A Halogen Leak Detector. See Special Tools .

J 39400-A Halogen Leak Detector. See Special Tools .

J 44551 Suction Screen Kit. See Special Tools .

J 44551 Suction Screen Kit. See Special Tools .

1. J 39400-A Halogen Leak Detector. See «Special Tools»(ref-365250-S10056360502010070600000) .
2. J 46246 Valve Core Removal Tool. See «Special Tools»(ref-365250-S10056360502010070600000) .

J 39400-A Halogen Leak Detector. See Special Tools .

J 41425 A/C Line Repair Kit. See Special Tools .

Do not service the rear A/C or heater lines as a complete unit. Service the rear A/C or heater lines as a sectional repair.

You can obtain the various sections of line through GMSPO.

Use the J 41425 when any of the following actions damage the rear A/C or heater lines. See Special Tools .

1. Rub-through
2. Collision damage
3. Leakage in the system

Minimum Tube Length Required Table

Follow the Straight Line Repair procedure in order to repair line damage in a straight section of line.

Follow the Line Sectioning Repair procedure in order to repair any damage in a bend area. Do not repair the rear A/C or heater lines in a bend area, replace the lines. Maintaining the original line shape will prevent vibrations and rub-through.

Straight Line Repair

1. Recover the refrigerant, if repairing the A/C lines. Refer to «Refrigerant Recovery and Recharging»(ref-365250-S31567954842010070600000) .
2. Drain the coolant, if repairing the heater lines. Refer to «Cooling System Draining and Filling (Static Fill)»(ref-365258-S42715675352010070600000) or «Cooling System Draining and Filling (Vac N Fill)»(ref-365258-S15415891712010070600000) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-365243-S07204316382010070600000) .
4. Locate the area that requires repair.
5. Obtain a length of replacement line to make the repair.
6. Use a tubing cutter in order to cut and remove the section of damaged line.
7. Use a tubing cutter in order to cut the replacement line to length.
8. Use the cleaning pad from the J 41425 in order to clean any burrs or grease from the line ends. See «Special Tools»(ref-365250-S10056360502010070600000) . Be sure to clean at least 19 mm (0.75 in) from the line ends.
9. Use the LOK prep sealant in order to prep the line ends.
10. Apply one drop of the J 41425-3 sealing compound to the outside of each end of the line.
11. Insert the line ends into the LOK fitting.
12. Rotate the LOK fitting one complete turn in order to evenly distribute the sealing compound around the lines.
13. Install the correct LOK fitting jaws into the J 41425-1 tool.
14. Install the J 41425-1 tool over the LOK connectors. Verify that the LOK connector ends are positioned in the counter bores of the jaws.
15. Tighten the forcing screw of the J 41425-1 tool. When fully seated, the LOK connector collars will bottom out on the center shoulder of the LOK fitting.
16. Loosen the forcing screw and remove the J 41425-1 tool from the repaired line.
17. Repeat Steps 8-16 to repair the other end of the line.
18. Verify that the LOK fittings are correctly installed.
19. Lower the vehicle.
20. Refill the coolant, if drained. Refer to «Cooling System Draining and Filling (Static Fill)»(ref-365258-S42715675352010070600000) or «Cooling System Draining and Filling (Vac N Fill)»(ref-365258-S15415891712010070600000) .
21. Evacuate and recharge the refrigerant, if repairing the A/C lines. Refer to «Refrigerant Recovery and Recharging»(ref-365250-S31567954842010070600000) .

Line Sectioning Repair

1. Recover the refrigerant, if repairing the A/C lines. Refer to «Refrigerant Recovery and Recharging»(ref-365250-S31567954842010070600000) .
2. Drain the coolant, if repairing the heater lines. Refer to «Cooling System Draining and Filling (Static Fill)»(ref-365258-S42715675352010070600000) or «Cooling System Draining and Filling (Vac N Fill)»(ref-365258-S15415891712010070600000) .
3. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-365243-S07204316382010070600000) .
4. Obtain a new A/C or heater line for sectioning.
5. Scribe a mark on the line that will be sectioned.
6. Use a tubing cutter in order to cut the line or lines being replaced.
7. Remove the section of line being replaced from the vehicle.
8. Install the replacement line to the vehicle.
9. Use a tubing cutter in order to cut the replacement line to length.
10. Use the cleaning pad from the J 41425 in order to clean any burrs or grease. See «Special Tools»(ref-365250-S10056360502010070600000) . Be sure to clean at least 19 mm (0.75 in) from the A/C line.
11. Use the LOK prep sealant in order to prep the A/C or heater line.
12. Apply one drop of the J 41425-3 sealing compound to the outside of each line end.
13. Insert the line ends into the LOK fitting.
14. Rotate the LOK fitting one complete turn in order to evenly distribute the sealing compound around the lines.
15. Install the correct LOK fitting jaws into the J 41425-1 tool.
16. Install the J 41425-1 tool over the LOK connectors. Verify that the LOK connector ends are positioned in the counter bores of the jaws.
17. Hold the tool body with a 3/8-inch breaker bar. Turn the forcing screw until both of the connector collars bottom on the center shoulder of the LOK fitting.
18. Loosen the forcing screw. Remove the tool from the repaired line.
19. Verify that the LOK fitting is correctly installed.
20. Lower the vehicle.
21. Refill the coolant, if drained. Refer to «Cooling System Draining and Filling (Static Fill)»(ref-365258-S42715675352010070600000) or «Cooling System Draining and Filling (Vac N Fill)»(ref-365258-S15415891712010070600000) .
22. Evacuate and recharge the refrigerant, if repairing the A/C lines. Refer to «Refrigerant Recovery and Recharging»(ref-365250-S31567954842010070600000) .

Engine Coolant

Engine coolant is the key element of the heating system. The engine thermostat controls the normal engine operating coolant temperature. The thermostat also creates a restriction for the cooling system that promotes a positive coolant flow and helps prevent cavitation. Coolant enters the heater core through the inlet heater hose, in a pressurized state. The heater core is located inside the HVAC module. The ambient air drawn through the HVAC module absorbs the heat of the coolant flowing through the heater core. The HVAC module distributes heated air to the passenger compartment for consistent passenger comfort. Opening or closing the HVAC module temperature door controls the amount of heat delivered to the passenger compartment. The coolant exits the heater core through the return heater hose and is recirculated back through the engine cooling system.

A/C Cycle

The auxiliary A/C system operates from the vehicles primary A/C system. The front or primary A/C system must be ON to allow the rear A/C system to function.

Refrigerant is the key element in an air conditioning system. R-134a is presently the only EPA approved refrigerant for automotive use. R-134a is an very low temperature gas that can transfer the undesirable heat and moisture from the passenger compartment to the outside air.

The A/C compressor is belt driven and operates when the magnetic clutch is engaged. The compressor builds pressure on the vapor refrigerant. Compressing the refrigerant also adds heat to the refrigerant. The refrigerant is discharged from the compressor, through the discharge hose, and forced to flow to the condenser and then through the balance of the A/C system. The A/C system is mechanically protected with the use of a high pressure relief valve. If the high pressure switch were to fail or if the refrigerant system becomes restricted and refrigerant pressure continued to rise, the high pressure relief will pop open and release refrigerant from the system.

Compressed refrigerant enters the condenser in a high temperature, high pressure vapor state. As the refrigerant flows through the condenser, the heat of the refrigerant is transferred to the ambient air passing through the condenser. Cooling the refrigerant causes the refrigerant to condense and change from a vapor to a liquid state.

The condenser is located in front of the radiator for maximum heat transfer. The condenser is made of aluminum and aluminum cooling fins, which allows rapid heat transfer for the refrigerant. The semi-cooled liquid refrigerant exits the condenser and flows through the liquid line. The liquid line is split and the liquid refrigerant flows to both the front and rear thermal expansion valves.

There is a front and rear thermal expansion valve that is attached to the front and rear evaporators. The thermal expansion valve is the dividing point for the high and the low pressure sides of the A/C system. As the refrigerant passes through the thermal expansion valve, the pressure of the refrigerant is lowered. Due to the pressure differential of the liquid refrigerant, the refrigerant will begin to vaporize at the thermal expansion valve. The thermal expansion valve also meters the amount of liquid refrigerant that can flow into the evaporator.

Refrigerant exiting the thermal expansion valve flows into the evaporator core in a low pressure, liquid state. Ambient air is drawn through the HVAC module and passes through the evaporator core. Warm and moist air will cause the liquid refrigerant boil inside of the evaporator core. The boiling refrigerant absorbs heat from the ambient air and draws moisture onto the evaporator. The refrigerant exits the evaporator back through the thermal expansion valve and into the suction line and back to the compressor, in a vapor state completing the A/C cycle of heat removal. At the compressor, the refrigerant is compressed again and the cycle of heat removal is repeated.

The conditioned air is distributed through the HVAC module for passenger comfort. The heat and moisture removed from the passenger compartment will also change form, or condense, and is discharged from the HVAC module as water under the vehicle.