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 belts)

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 noise:

• Dynamic dumper looseness

• Exhaust system looseness

• Intake-air system looseness

Other noise:

• Camshaft friction gear noise or MLA noise

• Timing chain noise

STEP

INSPECTION

RESULTS

ACTION

1

Is a squealing, click or chirping sound present?

Yes

Inspect for the followings:

• Engine oil level

• Drive belt tension

• Splash shield or under cover looseness

• Generator installation (alignment)

No

Go to the next step.

2

Is a rumbling or grinding noise present?

Yes

Inspect for the followings:

• Drive belt tension

• P/S fluid level

No

Go to the next step.

3

Is a rattling noise present?

Yes

Inspect rattling location for loose parts.

No

Go to the next step.

4

Is a hissing noise 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 roar noise present?

Yes

Inspect looseness for followings:

• Dynamic dumper

• Intake-air system

• Exhaust system

No

Go to the next step.

6

Is a knocking noise present?

Yes

Go to symptom troubleshooting "No.11 Knocking/pinging".

(See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [LF].)

No

If the noise comes from the 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 SYMPTOM DIAGNOSTIC INDEX [LF].)

• If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis.

• If vehicle is repaired, troubleshooting completed.

• If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.

  (See PCM REMOVAL/INSTALLATION [LF].)