NO.21 ENGINE NOISE [L3]

BME010300000W23

21

ENGINE NOISE

DESCRIPTION

Engine noise from under hood

POSSIBLE CAUSE

Squeal, click or chirp noise:

• Improper engine oil level
• Improper drive belt tension

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

Rap or roar sound noise:

• Exhaust system looseness

Other noise:

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

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1
Is squeal, click or chirp sound present?
Yes
Inspect engine oil level or drive belts.
No
Go to next step.
2
Is rumble or grind sound present?
Yes
Inspect drive belts.
No
Go to next step.
3
Is rattle sound present?
Yes
Inspect location of rattle for loose parts.
No
Go to next step.
4
Is hiss sound present?
Yes
Inspect for following:
• Vacuum leakage
• Spark plug looseness
• Intake-air system leakage
No
Go to next step.
5
Is rap or roar sound present?
Yes
Inspect exhaust system for loose parts.
No
Go to next step.
6
Is knock sound present?
Yes
Go to symptom troubleshooting "No.11 Knocking/pinging".
No
If noise comes from engine internal, inspect for friction gear, timing chain or MLA noise.
7
Verify test results.
• If okay, return to diagnostic index to service any additional symptoms.
• If malfunction remains, replace PCM.