Volkswagen Corrado (1993 year). Manual - part 92

 

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Volkswagen Corrado (1993 year). Manual - part 92

 

 

A/C SYSTEM GENERAL DIAGNOSTIC PROCEDURES 

 HIGH   

³

  HIGH   

³

 Outlet air warm.            

³

 Compressor        

³

³

        

³

         

³

 Liquid line very hot.       

³

 Malfunction       

³

³

        

³

         

³

 Bubbles in sight glass.     

³

    or             

³

³

        

³

         

³

                             

³

 R-12 Overcharge   

³

ÃÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´
³

 HIGH   

³

  HIGH   

³

 Outlet air slightly cool.   

³

Large Amount of Air

³

³

        

³

         

³

 Bubbles in sight glass.     

³

 of Air & Moisture 

³

³

        

³

         

³

                             

³

 in System         

³

ÃÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´
³

 HIGH   

³

  HIGH   

³

 Outlet air warm.            

³

  Expansion Valve  

³

³

        

³

         

³

 Evaporator outlet sweating  

³

  Stuck Open       

³

³

        

³

         

³

 and frost.                  

³

                   

³

ÃÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´
³

(1) - If equipped with a low refrigerant charge  protection system, 

³

³

      compressor operation may have stopped.                        

³

ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ

         AIR CONDITIONING GENERAL TROUBLE SHOOTING

         CONDITION & POSSIBLE CAUSE

         Compressor Not Working
      *  Compressor clutch circuit open.
      *  Compressor clutch coil inoperative.
      *  Poor clutch ground connection.
      *  Fan belts loose.
      *  Thermostatic switch inoperative.
      *  Thermostatic switch not adjusted.
      *  Ambient temperature switch open.
      *  Superheat fuse blown.

         Excessive Noise or Vibration
      *  Missing or loose mounting bolts.
      *  Bad idler pulley bearings.
      *  Fan belts not tightened correctly.
      *  Compressor clutch contacting body.
      *  Excessive system pressure.
      *  Compressor oil level low.
      *  Damaged clutch bearings.
      *  Damaged reed valves.
      *  Damaged compressor.

         Insufficient or No Cooling; Compressor Working
      *  Expansion valve inoperative.
      *  Heater control valve stuck open.
      *  Low system pressure.
      *  Blocked condenser fins.
      *  Blocked evaporator fins.
      *  Vacuum system leak.
      *  Vacuum motors inoperative.
      *  Control cables improperly adjusted.

A/C SYSTEM GENERAL DIAGNOSTIC PROCEDURES 

         HEATING GENERAL TROUBLE SHOOTING

         CONDITION & POSSIBLE CAUSE

         Insufficient, Erratic, or No Heat
      *  Low coolant level.
      *  Incorrect thermostat.
      *  Restricted coolant flow through heater core.
      *  Heater hoses plugged.
      *  Misadjusted control cable.
      *  Sticking heater control valve.
      *  Vacuum hose leaking.
      *  Vacuum hose blocked.
      *  Vacuum motors inoperative.
      *  Blocked air inlet.
      *  Inoperative heater blower motor.
      *  Oil residue on heater core fins.
      *  Dirt on heater core fins.

         Too Much Heat
      *  Improperly adjusted cables.
      *  Sticking heater control valve.
      *  No vacuum to heater control valve.
      *  Temperature door stuck open.

         Airflow Changes During Acceleration
      *  Vacuum system leak.
      *  Bad check valve or reservoir.

         Air From Defroster At All Times
      *  Vacuum system leak.
      *  Improperly adjusted control cables.
      *  Inoperative vacuum motor.

         Blower Does Not Operate Correctly
      *  Blown fuse.
      *  Blower motor windings open.
      *  Resistors burned out.
      *  Motor ground connection loose.
      *  Wiring harness connections loose.
      *  Blower motor switch inoperative.
      *  Blower relay inoperative.
      *  Fan binding or foreign object in housing.
      *  Fan blades broken or bent.

END OF ARTICLE

A/C SYSTEM GENERAL SERVICING 

         1993 GENERAL SERVICING
         General Servicing Procedures

         USING R-12 & R-134a REFRIGERANT

         HANDLING/SAFETY PRECAUTIONS

         1) Always work in a well-ventilated, clean area. Refrigerant
R-134a is colorless and is invisible as a gas. Refrigerant (R-12 or R-
134a) is heavier than oxygen and will displace oxygen in a confined
area. Avoid breathing refrigerant vapors. Exposure may irritate eyes,
nose and throat.
         2) The system's high pressure can cause severe injury to eyes
and skin if a hose were to burst. Always wear eye protection when
working around A/C system and refrigerant. If necessary, wear rubber
gloves or other protective clothing.
         3) Refrigerant evaporates quickly when exposed to atmosphere,
freezing anything it contacts. If liquid refrigerant contacts eyes or
skin, DO NOT rub eyes or skin. Immediately flush affected area with
cool water for 15 minutes and consult a doctor or hospital.
         4) Never use R-134a in combination with compressed air for
leak testing. Pressurized R-134a in the presence of oxygen (air
concentrations greater than 60% by volume) may form a combustible
mixture. DO NOT introduce compressed air into R-134a containers (full
or empty), A/C system components or service equipment.
         5) DO NOT expose A/C system components to high temperatures,
steam cleaning for example, as excessive heat will cause
refrigerant/system pressure to increase. Never expose refrigerant
directly to open flame. If refrigerant needs to be warmed, place
bottom of refrigerant tank in warm water. Water temperature MUST NOT
exceed 125

ø

F (52

ø

C).

         6) Use care when handling refrigerant containers. DO NOT
drop, strike, puncture or incinerate containers. Use Department Of
Transportation (DOT) approved, DOT 4BW or DOT 4BA, refrigerant
containers.
         7) Never overfill refrigerant containers. The safe filling
level of a refrigerant container MUST NOT exceed 60% of the
container's gross weight rating. Store refrigerant containers at
temperature less than 125

ø

F (52

ø

C).

         8) R-12 refrigerant (Freon) will be sold and stored in White
containers, while R-134a refrigerant will be sold and stored in 30 or
50-pound Light Blue containers.
         9) R-12 and R-134a refrigerants must never be mixed, as their
desiccants and lubricants are not compatible. If the refrigerants are
mixed, system cross-contamination or A/C system component failure may
occur. Always use separate servicing and refrigerant
recovery/recycling equipment.
         10) Follow equipment manufacturer instructions of all service
equipment to be used. The Material Safety Data Sheet (MSDS), provided
by refrigerant manufacturer/suppliers, contains valuable information

A/C SYSTEM GENERAL SERVICING 

         IDENTIFYING R-134a SYSTEMS & COMPONENTS

         To prevent refrigerant cross-contamination, use following
methods to identify R-134a based systems and components.
         Fittings & "O" Rings
         All R-134a based A/C systems use 1/2" - 16" ACME threaded
fittings (identifiable by square threads) and quick-connect service
couplings. See Fig. 1. Besides the use of these fittings, most
manufacturers will use Green colored "O" rings in R-134a systems.

Fig. 1:  R-134a Fittings & Quick Connect Service Couplings ID
Courtesy of Audi of America, Inc.

         Underhood A/C Specification Labels
         Most R-134a based systems will be identified through the use
of Green or Light Blue underhood labels, or with R-134a refrigerant
clearly printed on labels. See Fig. 2. Some manufacturers will
identify R-12 based systems with White, Red, Silver or Gold underhood
labels. Before servicing an A/C system, always determine which
refrigerant is being used.

 

 

 

 

 

 

 

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