GM Storm/Spectrum 1985-1993 Repair Guide

Air Conditioning System

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SAFETY WARNINGS



  1. Avoid contact with a charged refrigeration system, even when working on another part of the air conditioning system or vehicle. If a heavy tool comes into contact with a section of air conditioning line, it can easily cause the relatively soft material to rupture.
  2.  
  3. When it is necessary to apply force to a fitting which contains refrigerant, as when checking that all system couplings are securely tightened, use a wrench on both parts of the fitting involved, if possible. This will avoid putting torque on the refrigerant tubing. (It is advisable, when possible, to use tube or line wrenches when tightening these flare nut fittings.)
  4.  

R-12 refrigerant is a chlorofluorocarbon which, when released into the atmosphere, can contribute to the depletion of the ozone layer in the upper atmosphere. Ozone filters out harmful radiation from the sun.

  1. Do not attempt to discharge the system by merely loosening a fitting, or removing the service valve caps and cracking these valves. Precise control is possible only when using the appropriate service gauges and a suitable recovery system. Place a rag under the open end of the charging hose while discharging the system to catch any drops of liquid that might escape. Wear protective gloves when connecting or disconnecting service gauge hoses.
  2.  
  3. Discharge the system only in a well ventilated area, as high concentrations of the gas can exclude oxygen and act as an anesthetic. When leak testing or soldering this is particularly important, as toxic gas is formed when R-12 contacts any flame.
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  5. Never start a system without first verifying that all service valves are properly installed and that all fittings throughout the system are snugly connected.
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  7. Avoid applying heat to any refrigerant line or storage vessel. Charging may be aided by using water heated to less than +125°F (+51°C) to warm the refrigerant container. Never allow a refrigerant storage container to sit out in the sun or near any other source of heat, such as a radiator.
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  9. Always wear goggles when working on a system to protect the eyes. If refrigerant contacts the eye, it is advisable in all cases to see a physician as soon as possible.
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  11. Frostbite from liquid refrigerant should be treated by first gradually warming the area with cool water, and then gently applying petroleum jelly. A physician should be consulted.
  12.  
  13. Always keep refrigerant can fittings capped when not in use. If the container is equipped with a safety cap to protect the valve, make sure the cap is in place when the can is not being used. Avoid sudden shock to the can which might occur from dropping it, or from banging a heavy tool against it. Never carry a can in the passenger compartment of a car.
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  15. Always completely discharge the system into a suitable recovery unit before painting the vehicle (if the paint is to be baked on), or before welding anywhere near the refrigerant lines.
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  17. When servicing the system, minimize the time that any refrigerant line or fitting is open to the air to prevent moisture or dirt which can damage the internal system components. Always replace O-rings on lines or fittings which are removed. Prior to installation coat, but do not soak, replacement O-rings with a suitable compressor oil.
  18.  

SYSTEM INSPECTION



The easiest and often most important check for the air conditioning system consists of a visual inspection of the system components. Visually inspect the air conditioning system for refrigerant leaks, damaged compressor clutch, compressor drive belt tension and condition, plugged evaporator drain tube, blocked condenser fins, disconnected or broken wires, blown fuses, corroded connections and poor insulation.

A refrigerant leak will usually appear as an oily residue at the leakage point in the system. The oily residue soon picks up dust or dirt particles from the surrounding air and appears greasy. Through time, this will build up and appear to be a heavy dirt impregnated grease. Most leaks are caused by damaged or missing O-ring seals at the component connections, damaged charging valve cores or missing service gauge port caps.

For a thorough visual and operational inspection, check the following:

  1. Inspect the air inlet duct and air deflector for missing or damaged parts which might affect air flow.
  2.  
  3. Check the surface of the radiator and condenser for dirt, leaves or other material which might block air flow.
  4.  
  5. Check for kinks in hoses and lines. Check the system for leaks.
  6.  
  7. Make sure the drive belt is under the proper tension. When the air conditioning is operating, make sure the drive belt is free of noise or slippage.
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  9. Make sure the blower motor operates at all appropriate positions, then check for equal distribution of the air from all outlets with the blower on HIGH .
  10.  

Keep in mind that under conditions of high humidity, air discharged from the A/C vents may not feel as cold as expected, even if the system is working properly. This is because the vaporized moisture in humid air retains heat more effectively than does dry air, making the humid air more difficult to cool.

  1. Make sure the air passage selection lever is operating correctly. Start the engine and warm it to normal operating temperature, then make sure the hot/cold selection lever is operating correctly.
  2.  

REFRIGERANT LEVEL CHECK



Spectrum and 1990-1991 Storm

See Figure 1

  1. Start the engine and run at fast idle, about 1500 rpm.
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  3. Operate the A/C at maximum cooling for several minutes.
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  5. Check the refrigerant level by looking through the sight glass provided on the top of the accumulator/dehydrator. To locate the accumulator, follow the refrigerant line from the condenser to the accumulator/dehydrator assembly. The other condenser line runs from the compressor.
  6.  
  7. Compare the symptoms visible through the sight glass to the conditions in the appropriate illustration, in order to determine coolant charge.
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Fig. Fig. 1: Refrigerant level check - looking through the accumulator/dehydrator sight glass

1992 and 1993 Storm

See Figure 2

  1. Install a suitable manifold gauge set.
  2.  
  3. Install a thermometer in the passenger compartment right center air outlet, then open the vehicle doors and windows to stabilize the vehicle interior with the ambient air temperature.
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  5. Ground the coolant fan check connector (the connector is on a WHITE wire and is located in the left rear of the engine compartment, above the power brake booster), then start the engine and allow it to idle.
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  7. Depress the A/C switch to the ON position, move the air source lever to the recirculation position, set the temperature lever to full cold and select the 3rd blower speed.
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  9. When the engine is fully warmed, run the engine at 2000 rpm. Continue to run the engine until the system pressure and outlet temperature stabilize. This should take about 5 minutes.
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  11. Record the pressure and temperature readings, then compare them to the specifications in the appropriate illustration. Remember that humidity can greatly affect A/C performance. System pressures and outlet temperatures can be expected to increase 5-10 percent under humidity conditions of 70 percent or higher.
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Click image to see an enlarged view

Fig. Fig. 2: A/C performance test - 1992 and 1993 Storm

GAUGE SETS



See Figures 3, 4 and 5

Most of the service work performed in air conditioning requires the use of a set of two gauges, one for the high pressure side of the system and the other for the low pressure side of the system.

The low side gauge records both pressure and vacuum. Vacuum readings are calibrated from 0 to 30 in. Hg and the pressure graduations read from 0 to no less than 60 psi (414kpa). The high side gauge measures pressure from 0 to at least 600 psi (4140kpa).

Both gauges are threaded into a manifold that contains two hand shut-off valves. Proper manipulation of these valves, and the use of the attached hoses allow the user to perform the following services:

  1. Test high and low side pressures.
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  3. Remove air, moisture, and contaminated refrigerant.
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  5. Purge the system (of refrigerant).
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  7. Charge the system (with refrigerant).
  8.  

The manifold valves are designed so they have no direct affect on gauge readings, but serve only to provide for, or cut off, flow of refrigerant through the manifold. During all testing and hook-up operations, the valves are kept in the closed position to avoid disturbing the refrigeration system. The valves are opened only to purge the system or to charge it.

Connect the manifold gauge set as follows:

  1. Make sure that both gauges read 0;, then close both valves.
  2.  
  3. Connect the low pressure gauge hose to the compressor suction port located on the suction hose (between the evaporator and compressor), then hand-tighten the hose nut.
  4.  
  5. Connect the high pressure gauge hose to the discharge service port located on the compressor discharge hose (between the compressor and condenser), then hand-tighten the hose nut.
  6.  



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Fig. Fig. 3: Example of an A/C system schematic - 1993 Storm shown



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Fig. Fig. 4: The high pressure hose service port - 1990 Storm



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Fig. Fig. 5: Low pressure hose service port - 1990 Storm

DISCHARGING THE SYSTEM



R-12 refrigerant is a chlorofluorocarbon which, when released into the atmosphere, can contribute to the depletion of the ozone layer in the upper atmosphere. Ozone filters out harmful radiation from the sun.

Consult the laws in your area before servicing the air conditioning system. In some states it is illegal to perform repairs involving refrigerant unless the work is done by a certified technician.

The use of refrigerant recovery systems and recycling stations makes possible the recovery and reuse of refrigerant after contaminants and moisture have been removed. If a recovery system or recycling station is available, the following general procedures should be observed, in addition to the operating instructions provided by the equipment manufacturer.

  1. Check the system for pressure using the manifold gauge set. Take note, if a recovery system is used to draw refrigerant from a system that is already ruptured and open to the atmosphere, only air may be pulled into the tank.
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  3. Connect the refrigerant recycling station hose(s) to the vehicle air conditioning service ports and the recovery station inlet fitting.
  4.  

Hoses should have shut off devices or check valves within 12 in. (305mm) of the hose end to minimize the introduction of air into the recycling station and to minimize the amount of refrigerant released when the hose(s) is disconnected.

  1. Turn the power to the recycling station ON to start the recovery process. Allow the recycling station to pump the refrigerant from the system until the station pressure goes into a vacuum. On some stations the pump will be shut off automatically by a low pressure switch in the electrical system. On other units it may be necessary to manually turn off the pump.
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  3. Once the recycling station has evacuated the vehicle air conditioning system, close the station inlet valve, if equipped. Then switch OFF the electrical power.
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  5. Allow the vehicle air conditioning system to remain closed for about 2 minutes. Observe the system vacuum level as shown on the gauge. If the pressure does not rise, disconnect the recycling station hose(s).
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  7. If the system pressure rises, repeat Steps 3, 4 and 5 until the vacuum level remains stable for 2 minutes.
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  9. If A/C oil is expelled during the discharge procedure, save the oil in order to measure the proper quantity which must be added to the system during charging.
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EVACUATING/CHARGING



Evacuating and charging the air conditioning system is a combined procedure in which the lines are purged, then refrigerant is added to the system in proper quantity. Charging is always conducted through the low pressure fitting in the pipe behind the compressor. NEVER attempt to charge the air conditioning through the high pressure side of the system.

  1. Properly connect a manifold gauge set, then connect the manifold to a vacuum pump.
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  3. Turn the vacuum pump ON and slowly open the high and low side valves to the pump. Allow the system to evacuate for 20-30 minutes, then note the gauge reading.
  4.  
  5. Close the gauge high and low side valves, then shut the pump OFF .
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  7. Watch the low side gauge for vacuum loss. If vacuum loss is in excess of 1 in. Hg (3.38 kPa), then leak test the system, repair the leaks and return to Step 1. Before leak testing, remember to disconnect the gauge high side connector from the service port.
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  9. If after 1-3 minutes, the loss is less than 1 in. Hg (3.38 kPa), then proceed with the system charging.
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  11. Disconnect the gauge high side connection from the service port and the gauge manifold from the vacuum pump.
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  13. If components were replaced, such as the compressor, add the amount of A/C oil recovered from the component to that expelled during the discharge procedure in order to arrive at the total amount of fresh A/C oil which must be added to the system. Be sure to use only the proper A/C oil that is specified for your vehicle's system. Place the appropriate amount of fresh oil in a clean container and submerge the center gauge manifold hose. Slowly open the low-side manifold valve and allow the vacuum to draw in the oil from the container, then quickly close the valve.
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  15. Connect the manifold connection (which was attached used to draw in the fresh oil) to an R-12 source. If you are using a refrigerant drum instead of a charging station, place the drum on a scale to determine the amount of refrigerant being used.
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  17. Open the source and low side gauge valve, then monitor the weight of the drum or the rate at which the charging system is introducing R-12 into the system.
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  19. When 0.5 lbs. (227 g) of R-12 has been added to the system, start the engine and turn the air conditioning system ON . Set the temperature lever to full cold, the blower speed on high and the selector lever to the upper outlets. Under this condition, slowly draw in the remainder of the R-12 charge. The total charge should range between 1.2-1.7 lbs depending on the model.
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  21. When the system is charged, turn the source valve OFF and continue to run the engine for 30 seconds in order to clear the gauges and lines.
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  23. With the engine still running, carefully remove the gauge low side hose from the suction pipe service fitting. Unscrew the connection rapidly to avoid excess refrigerant loss.
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CAUTION
If the hoses of the manifold gauge set disconnect from the gauge, NEVER remove a hose from the gauge while the other end of the hose is still connected to an air conditioning system service fitting. Because the service fitting check valve is depressed by the hose connection, this would cause a complete and uncontrolled discharge of the system. Serious personal injury could be caused by the escaping R-12

  1. Install the protective service fitting caps and hand-tighten.
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  3. Turn the engine OFF .
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  5. If an electronic leak tester is available, test the system for leaks.
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  7. If there are no leaks, perform the refrigerant level test to verify proper system charging.
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LEAK TESTING



See Figure 6

Whenever a refrigerant leak is suspected, begin by checking for leaks at the fittings and valves. Use of an electronic leak detector, if available is preferable. Follow the manufacturer's instructions carefully. Move the detector probe at approximately 1 in. per second in the suspected leak area. When escaping refrigerant gas is located, the ticking/beeping signal from the detector will increase in ticks/beeps per second. If the gas is relatively concentrated, the signal will be increasingly shrill.

If a tester is not available, perform a visual inspection and apply a soap solution to the questionable fitting or area. Bubbles will form to indicate a leak. Make sure to rinse the solution from the fitting before attempting repairs.



Click image to see an enlarged view

Fig. Fig. 6: A soap solution applied to the suspected area or fitting can be helpful in pinpointing a refrigerant leak

 
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