NO.21 ENGINE NOISE [ZJ, Z6]

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NO.21 ENGINE NOISE [ZJ, Z6]

B3E010318881W54

21 | ENGINE NOISE
--- | ---
DESCRIPTION | Engine noise from under hood

POSSIBLE CAUSE

Squeal, click or chirp noise:

• Improper engine oil level
• Improper drive belt tension
• Generator installation (alignment)
• Splash shield or under cover looseness (splashed water to drive belt)

Rattle sound noise:

• Loose parts

Hiss sound noise:

• Vacuum leakage
• Loose spark plug
• Air leakage from intake-air system

Rumble or grind noise:

• Improper drive belt tension
• Improper P/S fluid level

Rap or roar sound noise:

• Dynamic damper looseness
• Exhaust system looseness
• Intake-air system looseness

Other noise:

• Camshaft friction gear noise or MLA noise
• Timing chain noise

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
--- | --- | --- | ---
1 | Is a squealing, click or chirping sound present? | Yes | Inspect for following: • Engine oil • Drive belt tension • Splash shield or under cover looseness • Generator installation (alignment)
No | Go to the next step.
2 | Is a rumbling or grinding sound present? | Yes | Inspect drive belts.
No | Go to the next step.
3 | Is a rattling sound present? | Yes | Inspect rattling location for loose parts.
No | Go to the next step.
4 | Is a hissing sound present? | Yes | Inspect for the following: • Vacuum leakage • Spark plug looseness • Intake-air system leakage
No | Go to the next step.
5 | Is a rapping or roaring sound present? | Yes | Inspect the following for looseness: • Dynamic chamber • Intake-air system • Exhaust system
No | Go to the next step.
6 | Is a knocking sound present? | Yes | Go to symptom troubleshooting "No.11 Knocking/pinging". (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [ZJ, Z6].)
No | If noise comes from engine internal, inspect for friction gear, timing chain or MLA noise.

7

Verify test results.
• If normal, return to diagnostic index to service any additional symptoms.
(See ENGINE SYMPTOM TROUBLESHOOTING [ZJ, Z6].)
• If malfunction remains, inspect related Service information perform repair or diagnosis.

  - If vehicle repaired, troubleshooting completed.
  - If vehicle not repaired or additional diagnostic information not available, replace the PCM.
  (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [ZJ, Z6].)