No. 21 Engine Noise

POSSIBLE CAUSE

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

DIAGNOSTIC PROCEDURE

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)
1	Is a squealing, click or chirping sound present?	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
2	Is a rumbling or grinding noise present?	No	Go to the next step.
3	Is a rattling noise present?	Yes	Inspect rattling location for loose parts.
3	Is a rattling noise present?	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
4	Is a hissing noise present?	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
5	Is a rapping or roar noise present?	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 ).
6	Is a knocking noise present?	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 ENGINE SYMPTOM TROUBLESHOOTING ). 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 ).