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2008 - MX-5 - HVAC

NO.8 NOISE WHILE OPERATING A/C SYSTEM



8

Noise while operating A/C system.

DESCRIPTION

  • Noise from magnetic clutch, A/C compressor, hose or refrigerant line.

POSSIBLE CAUSE

  • Magnetic clutch operation noise

  • A/C compressor vane noise

  • A/C compressor slippage noise

  • Hose or refrigerant line interference noise


Diagnostic procedure

STEP

INSPECTION

ACTION

1

CHECK A/C COMPRESSOR VANE NOISE

  • Is there a jingling, popping, beeping, or buzzing sound (A/C compressor vane noise)?

Yes

Go to Step 5.

No

Go to the next step.

2

INSPECT A/C COMPRESSOR SLIPPAGE NOISE

  • Is there a squeaking or whirling sound (A/C compressor slippage noise)?

Yes

Go to Step 14.

No

Go to the next step.

3

INSPECT A/C COMPRESSOR INTERFERENCE NOISE

  • Is there a rattling or vibrating sound (interference noise)?

Yes

Go to Step 18.

No

Go to the next step.

4

INSPECT MAGNETIC CLUTCH OPERATION NOISE

  • Is there a clicking sound (magnetic clutch operation noise)?

Yes

Adjust clearance between pressure plate of magnetic clutch and A/C compressor pulley, then go to Step 19.

(See MAGNETIC CLUTCH ADJUSTMENT.)

No

Condition is normal. (Recheck malfunction symptoms.)

5

INSPECT A/C COMPRESSOR NOISE TIME

  • Is noise heard continuously for more than 3 s after A/C compressor comes on?

Yes

Go to the next step.

No

Condition is normal. (Noise occurs for 2—3 s immediately after A/C compressor turns on.)

6

INSPECT IDLE SPEED

Yes

Go to the next step.

No

Follow the repair instruction described in section F, then go to Step 19.

7

INSPECT REFRIGERANT AMOUNT

  • Inspect refrigerant amount.

  • Is it okay?

Yes

Go to Step 10.

No

Go to the next step.

8

INSPECT REFRIGERANT LINES

  • Inspect refrigerant lines.

    • Is piping free of damage and cracks?

    • Are piping connections free of oil grime? (Visual inspection)

    • Are piping connections free of gas leakage?

    • Are piping installation points on condenser free of gas leakage?

    • Are piping installation points on receiver/drier free of gas leakage?

    • Are piping installation points on A/C compressor free of gas leakage?

    • Are piping installation points on A/C unit free of gas leakage

    • Perform gas leak inspection using gas leak tester.

  • Are above items okay?

Yes

Go to the next step.

No

If piping or A/C component(s) is damaged or cracked, replace then go to Step 19.

If there is gas leakage, repair or replace connection and replace condenser*1, then go to Step 19.

9

INSPECT EVAPORATOR PIPING CONNECTIONS IN A/C UNIT FOR GAS LEAKAGE

  • Are piping connections for evaporator in A/C unit free of gas leakage?

Yes

Adjust refrigerant amount to specified level, then go to Step 19.

No

If piping is damaged or cracked, replace then go to Step 19.

If there is gas leakage, repair or replace connection and replace condenser*1, then go to Step 19.

10

CHECK TO SEE WHETHER MALFUNCTION IS IN COMPRESSOR OIL OR ELSEWHERE

  • Add 20 ml {20 cc, 0.8 fl oz} of compressor oil.

  • Is noise heard when racing engine?

Yes

Go to the next step.

No

Troubleshooting completed.

Explain repair to customer.

11

CHECK TO SEE WHETHER MALFUNCTION IS IN A/C COMPRESSOR OR ELSEWHERE

  • Drain compressor oil.

  • Is it contaminated with metal particles?

Yes

Go to the next step.

No

Replace A/C compressor, then go to Step 19. (See A/C COMPRESSOR REMOVAL/INSTALLATION.)

12

CHECK TO SEE WHETHER MALFUNCTION IS SOMEWHERE IN A/C SYSTEM OR ELSEWHERE

  • Is compressor oil whitish and mixed with water?

Yes

Replace A/C compressor, evaporator, expansion valve, condenser and refrigerant line, then go to Step 19. (See A/C COMPRESSOR REMOVAL/INSTALLATION.) (See A/C UNIT DISASSEMBLY/ASSEMBLY.) (See CONDENSER REMOVAL/INSTALLATION.) (See REFRIGERANT LINE REMOVAL/INSTALLATION.)

No

Go to the next step.

13

INSPECT A/C COMPRESSOR OIL

  • Is compressor oil darker than normal and contaminated with aluminum chips?

Yes

Replace A/C compressor and condenser, then go to Step 19. (Since A/C compressor may be worn and receiver/drier may be clogged, replacement of receiver/drier is necessary.) (See A/C COMPRESSOR REMOVAL/INSTALLATION.) (See CONDENSER REMOVAL/INSTALLATION.)

No

Condition is normal. Recheck malfunction symptoms.

14

CHECK TO SEE WHETHER MALFUNCTION IS IN A/C COMPRESSOR OR ELSEWHERE

  • Is noise heard immediately after A/C compressor is stopped?

Yes

Replace A/C compressor, then go to Step 19. (A/C compressor discharge valve left open) (See A/C COMPRESSOR REMOVAL/INSTALLATION.)

No

Go to the next step.

15

INSPECT DRIVE BELT

Yes

Go to the next step.

No

Adjust or replace drive belt, then go to Step 19.

16

INSPECT DRIVE BELT CONDITION

  • Is drive belt worn?

  • Does it have foreign material imbedded in it, or have oil on it?

Yes

Remove obstruction, remove oil, or replace drive belt, then go to Step 19.

No

Go to the next step.

17

INSPECT MAGNETIC CLUTCH

Yes

Replace A/C compressor (excluding pressure plate, A/C compressor pulley, and stator), then go to Step 19. (See A/C COMPRESSOR REMOVAL/INSTALLATION.)

No

Replace magnetic clutch, then go to Step 19. (See MAGNETIC CLUTCH DISASSEMBLY/ASSEMBLY.)

18

CHECK TO SEE WHETHER MALFUNCTION IS IN A/C COMPRESSOR OR REFRIGERANT LINES

  • Is noise emitted from A/C compressor?

Yes

Visually inspect A/C compressor, replace appropriate parts if necessary, then go to the next step.

No

If noise is due to refrigerant lines, repair detached or missing clips, tighten loose bolts, then go to the next step.

19

VERIFY THAT MALFUNCTION SYMPTOM OCCURS AFTER REPAIR

  • Has A/C compressor noise stopped?

Yes

Troubleshooting completed.

Explain repairs to customer.

No

Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.


*1
If there is gas leakage, air enters into the A/C system. The desiccant within the receiver/drier absorbs the moisture from the air and becomes saturated. If the A/C system is used in this condition, the inside of the A/C compressor will begin to rust due to this moisture, which may cause lock up or noise to occur. Therefore, replacement of the receiver/drier is necessary.


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