NO.21 ENGINE NOISE [MZI-3.7]

id0103d2802700

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

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.13 Knocking/pinging”. (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZI-3.7].)
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 SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].) ― If malfunction remains, inspect related Service 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 [MZI-3.7].)