NO.21 ENGINE NOISE [MZR 2.0, MZR 2.5]

id0103e1802700

21

ENGINE NOISE

DESCRIPTION

•  The engine noise from under bonnet.

POSSIBLE CAUSE

Squeal, click or chirp noise:

•  Improper engine oil level

•  Improper drive belt tension

•  Generator installation

•  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

Rap or roar noise:

•  Dynamic dumper looseness

•  Exhaust system looseness

•  Intake air system looseness

Other noise:

•  Tappet noise

•  Timing chain noise

•  PCM malfunction

21	ENGINE NOISE
DESCRIPTION	• The engine noise from under bonnet.
POSSIBLE CAUSE	Squeal, click or chirp noise: • Improper engine oil level • Improper drive belt tension • Generator installation • 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 Rap or roar noise: • Dynamic dumper looseness • Exhaust system looseness • Intake air system looseness Other noise: • Tappet noise • Timing chain noise • PCM malfunction

Diagnostic procedure

STEP	INSPECTION	RESULTS	ACTION
1	Is a squealing, click or chirping sound present?	Yes	Inspect the following: • Engine oil level • Drive belt tension • Splash shield or under cover looseness • Generator installation Repair or replace the malfunctioning part according to the inspection results.
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 the drive belt tension. Repair or replace the malfunctioning part according to the inspection results.
2	Is a rumbling or grinding noise present?	No	Go to the next step.
3	Is a rattling noise present?	Yes	Inspect the rattling location for loose parts. Repair or replace the malfunctioning part according to the inspection results.
3	Is a rattling noise present?	No	Go to the next step.
4	Is a hissing noise present?	Yes	Inspect the following: • Vacuum leakage • Spark plug looseness • Intake air system leakage Repair or replace the malfunctioning part according to the inspection results.
4	Is a hissing noise present?	No	Go to the next step.
5	Is a rapping or roar noise present?	Yes	Inspect for looseness in the following: • Dynamic dumper • Intake air system • Exhaust system Repair or replace the malfunctioning part according to the inspection results.
5	Is a rapping or roar noise present?	No	Go to the next step.
6	Is a knocking noise present?	Yes	Go to the symptom troubleshooting “NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE”. (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZR 2.0, MZR 2.5].)
6	Is a knocking noise present?	No	If the noise comes from inside the engine, inspect the tappet noise. Repair or replace the malfunctioning part according to the inspection results.
7	• Verify the test results. ― If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 2.0, MZR 2.5].) ― If a malfunction remains, inspect the related Service Information perform repair or diagnosis. • If the vehicle repaired, troubleshooting is completed. • If the vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5].)