Refrigerant Leak Testing
Note. General Motors vehicles are now manufactured with fluorescent dye installed directly into the air conditioning (A/C) system.
The fluorescent dye mixes and flows with the polyalkylene glycol (PAG) oil throughout the refrigerant system.
Verifying some passive leaks may require using the J 39400-A , even though the A/C system contains fluorescent dye. See Special Tools .
The only time that adding additional fluorescent dye is required is after flushing the A/C system.
Air Conditioning (A/C) System Performance Test
This test measures the operating efficiency of the A/C system under the following conditions
- The current ambient air temperature
- The current relative humidity
- The high side pressure of the A/C system
- The low side pressure of the A/C system
- The temperature of the air being discharged into the passenger compartment
Air Conditioning (A/C) Diagnostics - Pressure Zone A
| Step | Action | Value | Yes | No |
|---|
| DEFINITION: The high and low side pressures may be normal or slightly less than normal. Air Delivery Concern Slight Refrigerant Under Charge Refrigerant Contamination |
| 1 | Were you sent here from the A/C System Performance Test? | | Go to Step 2 | Go to Air Conditioning (A/C) System Performance Test |
| 2 | Refer to the instrument panel outlet air temperatures recorded during the A/C system performance test. Does the discharge air temperature between the right and left center instrument panel outlets vary by more than 1-2°C (2-3°F)? | | Go to Step 7 | Go to Step 3 |
| 3 | Did the customer mention that the A/C system output temperatures are good at first, but then turn warm during extended drives? | | Go to Step 4 | Go to Step 5 |
| 4 | Increase engine speed to 2000 RPM. During extended operation of the A/C system, does the low side pressure decrease, possibly accompanied by heavy frost on the liquid line between the expansion device and the evaporator? | | Go to Air Conditioning (A/C) Diagnostics - Pressure Zone D | Go to Step 5 |
| 5 | Refer to the pressures recorded during the A/C system performance test. Inspect for the following conditions: WARNING: Refer to Moving Parts and Hot Surfaces Warning . The high side pressure is slightly greater than the specified pressure ranges but still within Zone A on the A/C Pressure-Zone Classification Chart in the A/C System Performance Test. Refer to Air Conditioning (A/C) System Performance Test . The discharge line is hot. The suction line is cool. Do the listed conditions exist? | | Go to Step 7 | Go to Step 6 |
| 6 | Refer to the pressures recorded during the A/C system performance test. Inspect for the following conditions: The low side pressure is slightly lower than the specified pressure ranges but still within Zone A on the A/C Pressure-Zone Classification Chart in the A/C System Performance Test. Refer to Air Conditioning (A/C) System Performance Test . The discharge line is warm-to-hot. The suction line is cool-to-warm. Do the listed conditions exist? | | Go to Step 8 | Go to Air Temperature Malfunction for the manual system or Air Temperature Malfunction for the automatic system |
| 7 | The A/C system may be undercharged. Leak test A/C system. Refer to Leak Testing . Recharge the A/C system to specifications. Refer to Refrigerant Recovery and Recharging . Is the action complete? | | Go to Step 13 | |
| 8 | The A/C system may be contaminated. View the information screen on the J 43600 for detection of foreign gases in the A/C system. See Special Tools . Do foreign gases exist? | | Go to Step 9 | Go to Step 10 |
| 9 | Evacuate the A/C system to a scavenging tank. Refer to Refrigerant Recovery and Recharging . Recharge the A/C system to specifications. Is the action complete? | | Go to Step 13 | |
| 10 | The A/C system may contain too much moisture or air. Evacuate and recharge the A/C system to specifications. Refer to Refrigerant Recovery and Recharging . Operate the A/C system and inspect the instrument panel outlet air temperatures. Refer to Air Conditioning (A/C) System Performance Test . Are the instrument panel outlet air temperatures within the specified ranges of the A/C Performance Test Table? | | Go to Step 14 | Go to Step 11 |
| 11 | The A/C system may contain too much refrigerant oil. NOTE: Review the vehicles A/C repair history. If the vehicle history shows multiple A/C repairs and is suspected of improper PAG oil balancing in the previous repairs, perform the following procedure: Drain all of the PAG oil drain bottle on the ACR 2000. Flush the A/C system. Refer to Flushing . Was more than the total system capacity of refrigerant oil recovered from the ACR 2000 oil drain bottle? | 148 ml (5 oz) | Go to Step 12 | Go to Step 13 |
| 12 | Add the specified amount of refrigerant oil. Refer to Refrigerant System Capacities . Recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Are the actions complete? | | Go to Step 13 | |
| 13 | Record the low and high side pressures and the instrument panel outlet air temperature. Compare the instrument panel outlet air temperatures to those listed in the A/C System Performance Chart. Refer to Air Conditioning (A/C) System Performance Test . Are the high and low side pressures and the instrument panel outlet air temperatures within specifications? | | Go to Step 14 | |
| 14 | Operate the system in order to verify the repair. Did you find and correct the condition? | | System OK | Go to Symptoms - HVAC Systems - Manual or Go to Symptoms - HVAC Systems - Automatic |
| WARNING |
|---|
| Refer to Moving Parts and Hot Surfaces Warning . |
| NOTE |
|---|
| Review the vehicles A/C repair history. |
Air Conditioning (A/C) Diagnostics - Pressure Zone B
| Step | Action | Yes | No |
|---|
| DEFINITION: The low side pressure is higher than normal and the high side pressure is lower than normal. Malfunctioning A/C compressor Refrigerant under charge |
| 1 | Were you sent here from the A/C System Performance Test? | Go to Step 2 | Go to Air Conditioning (A/C) System Performance Test |
| 2 | After continued operation of the A/C system, do the low and the high side pressures equalize or become static? | Go to Step 5 | Go to Step 3 |
| 3 | Refer to the pressures recorded during the A/C System Performance Test. Inspect for the following conditions: WARNING: Refer to Moving Parts and Hot Surfaces Warning . The low side pressure is equal to or greater than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test . The high side pressure is less than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test . The low side refrigerant hose at the compressor feels cool-to-warm. The high side refrigerant hose at the compressor feels warm-to-hot. Do the listed conditions exist? | Go to Step 5 | Go to Step 4 |
| 4 | Refer to the pressures recorded during the A/C System Performance Test. Inspect for the following conditions: WARNING: Refer to Moving Parts and Hot Surfaces Warning . The low side pressure is greater than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test . The high side pressure is less than the specified pressure range of the A/C Performance Table. Refer to Air Conditioning (A/C) System Performance Test . The low side refrigerant hose at the compressor feels warm. The high side refrigerant hose at the compressor feels warm-to-hot. Do the listed conditions exist? | Go to Step 5 | Go to Air Conditioning (A/C) System Performance Test |
| 5 | The A/C system has a low refrigerant charge. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the procedure complete? | Go to Step 6 | |
| 6 | After you perform the repairs, record the following: The low and the high side pressures Instrument panel (I/P) outlet air temperature Compare the pressures and the temperature to those listed in the A/C Performance Chart. Refer to Air Conditioning (A/C) System Performance Test . Are the readings within the specified ranges found on the A/C Performance Chart? | Go to Step 13 | Go to Step 7 |
| 7 | The A/C compressor is malfunctioning. Remove the expansion device and inspect for contamination. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement . Did you find metal flakes on the expansion device? | Go to Step 9 | Go to Step 8 |
| 8 | Inspect the expansion device for a brown, powdery residue indicating desiccant in the A/C system. Is a brown, powdery residue present? | Go to Step 11 | Go to Step 12 |
| 9 | Remove the suction and the discharge hoses from the compressor. Refer to Discharge Hose Replacement and Suction Hose Replacement . Inspect for metal flake contamination at the line connections and the compressor ports. Is metal flake contamination present? | Go to Step 10 | Go to Step 12 |
| 10 | Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement . Replace the thermal expansion valve. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement . Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the repair complete? | Go to Step 13 | |
| 11 | Flush the A/C system. Refer to Flushing . Replace the thermal expansion valve. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement . Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement . Replace the desiccant bag. Refer to Air Conditioning Refrigerant Desiccant Replacement . Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the repair complete? | Go to Step 13 | |
| 12 | Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement . Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the repair complete? | Go to Step 13 | |
| 13 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Symptoms - HVAC Systems - Manual or Go to Symptoms - HVAC Systems - Automatic |
| WARNING |
|---|
| Refer to Moving Parts and Hot Surfaces Warning . |
| WARNING |
|---|
| Refer to Moving Parts and Hot Surfaces Warning . |
Air Conditioning (A/C) Diagnostics - Pressure Zone C
| Step | Action | Yes | No |
|---|
| DEFINITION: The low and the high side pressures are both higher than normal. Restricted Condenser Air Flow Cooling Fan Malfunction Expansion Device Malfunction |
| 1 | Were you sent here from the A/C System Performance Test? | Go to Step 2 | Go to Air Conditioning (A/C) System Performance Test |
| 2 | Start the engine. Turn ON the A/C. Inspect for proper cooling fan operation. Refer to Cooling Fan Description and Operation . Are the cooling fans ON and operating properly? | Go to Step 3 | Go to Step 5 |
| 3 | Visually inspect for the following conditions: Damaged condenser cooling fins Missing or misaligned air baffles Restricted air flow Do any of these conditions exist? | Go to Step 4 | Go to Step 6 |
| 4 | Repair the air flow restriction. Is the action complete? | Go to Step 9 | |
| 5 | Repair the fault to the cooling fan operation. Refer to Cooling Fan Inoperative . Is the repair complete? | Go to Step 9 | |
| 6 | WARNING: Refer to Moving Parts and Hot Surfaces Warning . Feel the liquid line on both sides of the expansion device.Are the temperatures on both sides of the expansion device similar? | Go to Step 7 | Go to Step 8 |
| 7 | Replace the damaged or faulty thermal expansion valve. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement . Is the action complete? | Go to Step 9 | |
| 8 | Air is in the refrigerant system, or the system is overcharged. Refer to the view screen on J 43600 for foreign gas content in the refrigerant. See Special Tools . Recover and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the action complete? | Go to Step 9 | |
| 9 | Record the low and high side pressures and the instrument panel outlet air temperature after you have performed the repairs. Compare the pressures and the instrument panel outlet air temperature to those listed in the A/C Performance Chart. Refer to Air Conditioning (A/C) System Performance Test . Are the readings within the specified ranges listed in the A/C Performance Chart? | Go to Step 10 | Go to Air Conditioning (A/C) System Performance Test |
| 10 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Symptoms - HVAC Systems - Manual or Go to Symptoms - HVAC Systems - Automatic |
| WARNING |
|---|
| Refer to Moving Parts and Hot Surfaces Warning . |
Air Conditioning (A/C) Diagnostics - Pressure Zone D
| Step | Action | Yes | No |
|---|
| DEFINITION: The low side pressure is lower than normal and the high side pressure is higher than normal. A restriction in the A/C system Debris in the system |
| 1 | Were you sent here from the A/C System Performance Test? | Go to Step 2 | Go to Air Conditioning (A/C) System Performance Test |
| 2 | WARNING: Refer to Moving Parts and Hot Surfaces Warning . Feel the liquid line before the expansion device.Is the liquid line cold before the expansion device? | Go to Step 3 | Go to Step 8 |
| 3 | Feel along the surfaces of the following high side components: The compressor discharge hose The condenser The liquid line between the condenser and the expansion device Did you detect an abrupt drop in temperature along the surfaces of any of the listed components? | Go to Step 7 | Go to Step 4 |
| 4 | Feel the liquid line at the expansion device location for extreme cold, possibly accompanied by heavy frost. Feel along the liquid line beyond the expansion device location for warm temperature. Is the liquid line extremely cold at the expansion device location and warm beyond the expansion device location? | Go to Step 11 | Go to Step 5 |
| 5 | Feel along the surfaces of the following low side components: The evaporator inlet tube between the expansion device and the evaporator core The evaporator outlet tube between the evaporator core and the compressor suction hose The compressor suction hose Did you feel an abrupt temperature change along the surfaces of any of the listed components? | Go to Step 7 | Go to Step 6 |
| 6 | Feel along the surfaces of the low and the high side components: The evaporator inlet tube between the expansion device and the evaporator core The evaporator outlet tube and the compressor The compressor suction hose The compressor discharge hose The condenser The evaporator inlet tube between the condenser and the expansion device Are the temperatures of these components only mildly warm? | Go to Step 14 | Go to Step 8 |
| 7 | Recover the refrigerant. Refer to Refrigerant Recovery and Recharging . Remove the restriction from the component, or replace the component which produced an abrupt temperature drop. Is the repair complete? | Go to Step 9 | |
| 8 | Recover the refrigerant and evacuate the system. Refer to Refrigerant Recovery and Recharging . Record the weight of the recovered refrigerant. Compare the weight of the recovered refrigerant with the system capacity. Refer to Refrigerant System Capacities . Is the weight of the recovered refrigerant charge greater than 75 percent of the total system capacity? | Go to Step 9 | Go to Step 10 |
| 9 | Recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the cooling performance improved? | Go to Step 21 | Go to Step 10 |
| 10 | Leak test the system. Refer to Leak Testing . Repair any leaks. Is the repair complete? | Go to Step 21 | |
| 11 | The expansion device is restricted. Replace the expansion device. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement . Are metal flakes present? | Go to Step 12 | Go to Step 13 |
| 12 | Remove the suction hose from the vehicle. Refer to Suction Hose Replacement . Inspect the hose for debris by blowing shop air through one end of the hose while covering the other end with a shop towel. Observe the amount of debris collected in the shop towel. Did a large amount of debris collect in the shop towel? | Go to Step 18 | Go to Step 20 |
| 13 | If the expansion device was restricted with a brown or black residue, perform the following procedure: Flush the A/C system. Refer to Flushing . Replace the desiccant bag. Refer to Air Conditioning Refrigerant Desiccant Replacement . Are the repairs complete? | Go to Step 21 | |
| 14 | Recover the refrigerant. Refer to Refrigerant Recovery and Recharging . Disconnect the suction and the discharge hoses from the compressor. Refer to Discharge Hose Replacement and Suction Hose Replacement . Inspect for the presence of debris in the compressor suction port. Is debris present in the compressor suction port? | Go to Step 15 | Go to Step 19 |
| 15 | Remove the debris from the suction port. Inspect the expansion device for damage or debris. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement . Did you find evidence of damage or debris? | Go to Step 17 | Go to Step 16 |
| 16 | If the expansion device does not show any signs of damage or debris, perform the following procedure: Remove the suction hose from the vehicle. Refer to Suction Hose Replacement . Inspect the hose for debris by blowing shop air through one end of the hose while covering the other end with a shop towel. Observe the amount of debris collected in the shop towel. Did a large amount of debris collect in the shop towel? | Go to Step 18 | Go to Step 19 |
| 17 | Replace the expansion device. Refer to Air Conditioning Evaporator Thermal Expansion Valve Replacement . If the expansion device was restricted, observe the type of debris present. Are metal flakes present? | Go to Step 12 | Go to Step 13 |
| 18 | If a large amount of debris was collected in the shop towel from the suction hose, replace the desiccant bag. Refer to Air Conditioning Refrigerant Desiccant Replacement . Is the repair complete? | Go to Step 19 | |
| 19 | Install the suction and the discharge hoses. Refer to Discharge Hose Replacement and Suction Hose Replacement . Are the repairs complete? | Go to Step 21 | |
| 20 | Install the suction and the discharge lines. Refer to Discharge Hose Replacement and Suction Hose Replacement . Recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Are the repairs complete? | Go to Step 21 | |
| 21 | Record the low and the high side pressures and the panel outlet air temperature after you perform the repairs. Compare the pressures and the panel outlet temperature to those listed in the A/C Performance Chart. Refer to Air Conditioning (A/C) System Performance Test . Are the readings within the specified ranges as shown on the A/C Performance Chart? | Go to Step 22 | Go to Air Conditioning (A/C) System Performance Test |
| 22 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Symptoms - HVAC Systems - Manual or Go to Symptoms - HVAC Systems - Automatic |
| WARNING |
|---|
| Refer to Moving Parts and Hot Surfaces Warning . |
Heating Performance Diagnostic
| Step | Action | Yes | No |
|---|
| DEFINITION: Heating system performance. |
| 1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual or Go to Symptoms - HVAC Systems - Automatic |
| 2 | Start the engine. Allow the engine to idle. Does the engine reach a normal operating temperature? | Go to Step 3 | Go to Step 9 |
| 3 | WARNING: Refer to Moving Parts and Hot Surfaces Warning . Allow the engine to idle. Select the FLOOR mode. Select the minimum blower speed. Select the warmest temperature setting. Feel the temperature of the inlet and outlet heater hoses at the heater core. Does the inlet heater hose feel warmer than the outlet heater hose? | Go to Step 7 | Go to Step 4 |
| 4 | Install a thermometer into the center IP PANEL air outlet. Secure a thermometer to the heater core outlet hose. Select the PANEL mode. Select the maximum blower speed. Select the warmest temperature setting. Record the temperature at the following locations: The center IP PANEL air outlet The heater core outlet hose Compare the recorded temperatures. Are the two temperature readings about equal? | Go to Step 5 | Go to Step 6 |
| 5 | Inspect and repair the following areas of the vehicle for cold air leaks: The cowl The recirculation door The HVAC module case Perform the necessary repairs. Are the repairs complete? | Go to Step 10 | |
| 6 | Inspect the temperature door operation. Refer to Diagnostic System Check - Vehicle . Perform any necessary repairs. Are the repairs complete? | Go to Step 10 | |
| 7 | Turn OFF the engine. Backflush the heater core. Start the engine. Select the FLOOR mode. Select the minimum blower speed. Select the warmest temperature setting. Feel the temperature of the inlet and outlet heater hoses at the heater core. Does the inlet heater hose feel warmer than the outlet heater hose? | Go to Step 8 | Go to Step 10 |
| 8 | Replace the heater core. Refer to Heater Core Replacement . Is the repair complete? | Go to Step 10 | |
| 9 | Repair the low engine temperature concern. Refer to Engine Fails To Reach Normal Operating Temperature . Is the repair complete? | Go to Step 10 | |
| 10 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2 |
| WARNING |
|---|
| Refer to Moving Parts and Hot Surfaces Warning . |
Noise Diagnosis - Auxiliary Blower Motor
| Step | Action | Yes | No |
|---|
| 1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual or Go to Symptoms - HVAC Systems - Automatic |
| 2 | Sit inside the vehicle. Close the vehicle doors and windows. Turn ON the ignition, with the engine OFF. Cycle the auxiliary blower motor through all of the speeds and modes in order to determine where and when the noise occurs. Is a noise evident during auxiliary blower operation? | Go to Step 3 | Go to Step 10 |
| 3 | Does the noise vary with the auxiliary blower speed? | Go to Step 4 | Go to Step 5 |
| 4 | Inspect for excessive vibration at each auxiliary blower motor speed by feeling the auxiliary blower case. Is excess vibration present? | Go to Step 5 | Go to Step 10 |
| 5 | Remove the auxiliary blower motor. Refer to Auxiliary Blower Motor Replacement . Inspect the auxiliary blower motor for deposits of foreign material. Did you find foreign material on the auxiliary blower motor? | Go to Step 7 | Go to Step 6 |
| 6 | Inspect the auxiliary blower motor for the following conditions: Cracked blades A loose impeller retainer Improper impeller alignment Did you find any of these conditions? | Go to Step 8 | Go to Step 9 |
| 7 | Remove the foreign material. Is the action complete? | Go to Step 10 | |
| 8 | Replace the auxiliary blower motor. Refer to Auxiliary Blower Motor Replacement . Is the action complete? | Go to Step 10 | |
| 9 | Install the auxiliary blower motor. Refer to Auxiliary Blower Motor Replacement . Is the action complete? | Go to Step 10 | |
| 10 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2 |
Noise Diagnosis - Blower Motor
| Step | Action | Yes | No |
|---|
| 1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual or Symptoms - HVAC Systems - Automatic |
| 2 | Inspect the air inlet grille for debris. Is debris present? | Go to Step 8 | Go to Step 3 |
| 3 | Sit inside the vehicle. Close the vehicle doors and windows. Turn ON the ignition, with the engine OFF. Cycle the blower motor through all of the speeds and modes in order to determine where and when the noise occurs. Is a noise evident during the blower operation? | Go to Step 4 | Go to Step 11 |
| 4 | Inspect for excessive vibration at each blower motor speed by feeling the blower case. Is excess vibration present? | Go to Step 6 | Go to Step 5 |
| 5 | Listen to the blower motor at each speed. Is the blower motor making a squeaking or chirping noise? | Go to Step 9 | Go to Step 11 |
| 6 | Remove the blower motor. Refer to Blower Motor Replacement . Inspect the blower motor impeller for deposits of foreign material. Inspect the blower motor for deposits of foreign material. Did you find any foreign material on the blower motor or blower motor impeller? | Go to Step 8 | Go to Step 7 |
| 7 | Inspect the blower motor for the following conditions: Cracked blades A loose impeller retainer Improper impeller alignment Did you find any of these conditions? | Go to Step 9 | Go to Step 10 |
| 8 | Remove the foreign material. Is the action complete? | Go to Step 10 | |
| 9 | Replace the blower motor. Refer to Blower Motor Replacement . Is the repair complete? | Go to Step 11 | |
| 10 | Install the blower motor. Refer to Blower Motor Replacement . Is the action complete? | Go to Step 11 | |
| 11 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2 |
Air Conditioning Compressor Oil Diagnosis
Note. To avoid repeat compressor failure, always inspect the condition of the refrigerant oil and take the appropriate corrective action before installing the replacement compressor.
| Condition | Corrective Action |
|---|
| Clean Oil no debris present | No corrective action necessary. |
| Clean Oil with debris present | Inspect the suction port of the replacement compressor for presence of a suction screen. If the Replacement Compressor does NOT contain a suction screen, Install Suction Screen in the line. Replace desiccant or component containing the desiccant. Replace desiccant filter if applicable. Remove and inspect high pressure side filter (if applicable). Remove, inspect, clean, or replace orifice tube. If the system has a front orifice tube and is equipped with a filter in the rear auxiliary line, remove, inspect, clean, or replace the filter. If the system has a front orifice tube and is not equipped with a filter in the rear auxiliary line, remove the filter in the auxiliary TXV and Install a universal inline A/C Filter P/N 89016656 (AC Delco P/N 15-10413) as close to the rear TXV as possible. |
| Dark brown/black and/or pungent/unusual odor with no debris present | Replace desiccant or component containing the desiccant. Replace desiccant filter if applicable. Flush refrigerant system. |
| Dark brown/black and/or pungent/unusual odor with debris present | Replace desiccant or component containing the desiccant. Replace desiccant filter if applicable. Flush refrigerant system. Inspect the suction port of the replacement compressor for presence of a suction screen. If the replacement compressor does NOT contain a suction screen, install suction screen. Remove and inspect high pressure side filter (if applicable). Remove, inspect, clean, or replace orifice tube. If the system has a front orifice tube and is equipped with a filter in the rear auxiliary line, remove, inspect, clean, or replace the filter. If the system has a front orifice tube and is not equipped with a filter in the rear auxiliary line, remove the filter in the auxiliary TXV and install a universal inline A/C Filter P/N 89016656 (AC Delco P/N 15-10413) as close to the rear TXV as possible. |
| Oil Overcharge | Flush refrigerant system. |
| Refrigerant Contamination | Flush refrigerant system. |
| Hybrid Polyolester Refrigerant Oil (POE) Contamination | Flush refrigerant system. Replace desiccant or component containing the desiccant. Replace desiccant filter if applicable. |
Noise Diagnosis - Air Conditioning (A/C) System
| Step | Action | Yes | No |
|---|
| DEFINITION: Noise originating from the A/C compressor, drive belt or the A/C lines. |
| 1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual or Go to Symptoms - HVAC Systems - Automatic |
| 2 | A/C system noises can be generally categorized into three areas: Screeching, squealing, chirping noises Moaning noises Vibration/rattle noises Start the engine. Ensure that the A/C is ON. Is a screeching, squealing noise heard when the A/C is engaged? | Go to Step 3 | Go to Step 9 |
| 3 | With the engine OFF, inspect the drive belt for excessive wear. Refer to Drive Belt Falls Off and Excessive Wear Diagnosis . Is the drive belt excessively worn? | Go to Step 18 | Go to Step 4 |
| 4 | Inspect the drive belt tension. Refer to Drive Belt Tensioner Diagnosis . Is the drive belt tension correct? | Go to Step 5 | Go to Step 19 |
| 5 | Inspect the drive belt for excessive oil coverage. Is the drive belt covered with oil? | Go to Step 17 | Go to Step 6 |
| 6 | Start the engine. Ensure that the A/C is ON. Inspect the compressor and the clutch. Is the A/C compressor locked up? | Go to Step 24 | Go to Step 7 |
| 7 | Is the A/C compressor clutch slipping? | Go to Step 23 | Go to Step 8 |
| 8 | WARNING: Refer to Moving Parts and Hot Surfaces Warning . Using a stethoscope, listen to the A/C compressor for any abnormal noises.Is the compressor causing an abnormal noise? | Go to Step 15 | Go to Step 10 |
| 9 | Does a moaning noise exist when the A/C clutch is engaged? | Go to Step 10 | Go to Step 12 |
| 10 | Listen to the A/C compressor components and mounting for noise concerns using a stethoscope. Are any of these components loose, damaged or excessively worn? | Go to Step 20 | Go to Step 11 |
| 11 | Idle the engine. Engage the A/C compressor clutch. Using a stethoscope, move around the entire refrigerant plumbing system. Listening for any abnormal noises caused by a component of the A/C system touching another component. Are any of the A/C components grounding out and causing a vibration noise? | Go to Step 22 | Go to Step 13 |
| 12 | Does a vibration or rattle noise exist when the A/C clutch is engaged? | Go to Step 13 | Go to Step 14 |
| 13 | Does the noise stop when the A/C clutch is disengaged? | Go to Step 15 | Go to Step 25 |
| 14 | Idle the engine in PARK with the A/C compressor clutch engaged. Using a stethoscope, move around the entire A/C system testing for any abnormal noises caused by a component. Do any of the A/C components cause an abnormal noise? | Go to Step 21 | Go to Step 25 |
| 15 | Verify that the A/C system is properly charged. Refer to Refrigerant System Capacities . Is the A/C system properly charged? | Go to Step 26 | Go to Step 16 |
| 16 | Recharge the A/C system to specification. Refer to Refrigerant Recovery and Recharging . Is the abnormal compressor noise still present? | Go to Step 24 | Go to Step 26 |
| 17 | Repair the oil leak. Refer to Oil Leak Diagnosis . Is the repair complete? | Go to Step 18 | |
| 18 | Replace the drive belt. Refer to Drive Belt Replacement . Is the replacement complete? | Go to Step 26 | |
| 19 | Replace the drive belt tensioner. Refer to Drive Belt Tensioner Replacement . Is the replacement complete? | Go to Step 26 | |
| 20 | Repair or replace the A/C compressor mounting component. Is the repair complete? | Go to Step 26 | |
| 21 | Repair or replace the component which is causing the moaning concern as needed. Is the repair complete? | Go to Step 26 | |
| 22 | Correctly route or insulate the A/C component. Is the repair complete? | Go to Step 26 | |
| 23 | Replace the A/C compressor clutch. Refer to Air Conditioning Clutch Assembly Replacement . Is the repair complete? | Go to Step 26 | |
| 24 | Replace the A/C compressor. Refer to Air Conditioning Compressor Replacement . Is the repair complete? | Go to Step 26 | |
| 25 | The concern may be caused by an engine related component. Refer to Vibration Analysis - Engine . Did you find and correct the condition? | Go to Step 26 | |
| 26 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2 |
| WARNING |
|---|
| Refer to Moving Parts and Hot Surfaces Warning . |
Noise Diagnosis - HVAC Module
| Step | Action | Yes | No |
|---|
| 1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual or Go to Symptoms - HVAC Systems - Automatic |
| 2 | Start the engine. Cycle through all of the following: Blower motor speeds HVAC modes Temperature control settings Determine the type of noise: Scrape, pop Tick/click, chirp or groaning Air rush/whistle Is a scrape or pop noise evident when selecting modes or temperature settings? | Go to Step 6 | Go to Step 3 |
| 3 | Is a tick/click, chirping, groaning or scraping noise present, but decreases as blower motor speed is decreased? | Go to Step 6 | Go to Step 4 |
| 4 | Is an air rush/whistle noise evident in all modes but not all temperature settings? | Go to Step 6 | Go to Step 5 |
| 5 | Is an air rush/whistle noise evident only in defrost or floor mode? | Go to Step 6 | Go to Step 6 |
| 6 | Remove the instrument panel I/P carrier. Refer to Instrument Panel Carrier Replacement . Is the action complete? | Go to Step 7 | |
| 7 | Inspect the air flow doors for proper operation. Inspect the ducts for obstructions or foreign materials. Were any of these conditions found? | Go to Step 10 | Go to Step 8 |
| 8 | Inspect the mode and temperature doors and seals for warping or cracking. Are the doors in normal condition? | Go to Step 11 | Go to Step 9 |
| 9 | Replace the appropriate door and/or seals. Is the repair complete? | Go to Step 11 | |
| 10 | Remove any obstructions or foreign material found. Is the action complete? | Go to Step 11 | |
| 11 | Install the I/P carrier. Refer to Instrument Panel Carrier Replacement . Is the action complete? | Go to Step 12 | |
| 12 | Operate the system to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2 |
Odor Diagnosis
| Step | Action | Yes | No |
|---|
| DEFINITION: Odor originating or noticed through the HVAC system. |
| 1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual or Go to Symptoms - HVAC Systems - Automatic |
| 2 | Sit inside the vehicle. Close all of the doors and windows. Start the engine. Allow the engine idle at normal operating temperature. Select the maximum blower speed. Select the PANEL air outlet mode. Select the coldest temperature setting. Cycle through all of the blower speeds, modes and temperatures to define what type of odor is present. Musty smell Coolant smell Oil smell Does the odor have a musty smell? | Go to Step 3 | Go to Step 8 |
| 3 | Inspect the HVAC filter and the air inlet grille for debris. Is debris present? | Go to Step 4 | Go to Step 5 |
| 4 | Remove any debris. Is the action complete? | Go to Step 15 | |
| 5 | Inspect for wet carpeting. Is the carpet wet? | Go to Step 6 | Go to Step 14 |
| 6 | Inspect for the following conditions: Water leaks around the windshield Blockage of the HVAC module drain Leaks around the door seals Is a leak present? | Go to Step 7 | Go to Step 14 |
| 7 | Repair the leak as necessary. Is the repair complete? | Go to Step 15 | |
| 8 | Does the odor have a coolant smell? | Go to Step 9 | Go to Step 12 |
| 9 | Inspect the cooling system for leaks. Refer to Loss of Coolant . Is a leak present? | Go to Step 10 | Go to Step 12 |
| 10 | Inspect for coolant leaking inside the vehicle or for a film build-up on the windshield. Is the condition present? | Go to Step 11 | Go to Step 15 |
| 11 | Replace the heater core. Refer to Heater Core Replacement . Is the repair complete? | Go to Step 15 | |
| 12 | Does the odor have an oily smell? | Go to Step 13 | Go to Step 15 |
| 13 | Inspect the engine compartment for any leaks. Refer to the following procedures: Oil Consumption Diagnosis Fluid Leak Diagnosis Repair any oil leaks. Is the repair complete? | Go to Step 15 | |
| 14 | A musty odor can be caused by mold or mildew build-up on the evaporator or the heater core or inside of the HVAC module. Refer to Odor Correction . Is the action complete? | Go to Step 15 | |
| 15 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2 |
