NO.21 ENGINE NOISE [MZR 1.8, MZR 2.0, MZR 2.5]

id0103d4802700

21

ENGINE NOISE

DESCRIPTION

•  Engine noise from under bonnet.

POSSIBLE CAUSE

Squeal, click or chirp noise:

•  Improper engine oil level

•  Loose installation of solenoid valves

•  Improper drive belt tension

•  Generator mis-installation

•  Splash shield or under cover looseness (splashed water to drive belts)

Rumble or grind noise:

•  Improper drive belt tension

•  Loose parts

Rattle sound noise:

•  Loose parts

Hiss sound noise:

•  Air leakage from intake air system

•  Loose spark plug

•  Vacuum leakage

Rap or roar noise:

•  Dynamic dumper looseness

•  Exhaust system looseness

•  Intake air system looseness

•  Variable valve timing actuator malfunction (MZR 2.0, MZR 2.5)

•  Variable tumble control system malfunction

•  Improper balancer unit backlash (MZR 2.5)

Other noise:

•  Tappet noise

•  Timing chain noise

21	ENGINE NOISE
DESCRIPTION	• Engine noise from under bonnet.
POSSIBLE CAUSE	Squeal, click or chirp noise: • Improper engine oil level • Loose installation of solenoid valves • Improper drive belt tension • Generator mis-installation • Splash shield or under cover looseness (splashed water to drive belts) Rumble or grind noise: • Improper drive belt tension • Loose parts Rattle sound noise: • Loose parts Hiss sound noise: • Air leakage from intake air system • Loose spark plug • Vacuum leakage Rap or roar noise: • Dynamic dumper looseness • Exhaust system looseness • Intake air system looseness • Variable valve timing actuator malfunction (MZR 2.0, MZR 2.5) • Variable tumble control system malfunction • Improper balancer unit backlash (MZR 2.5) Other noise: • Tappet noise • Timing chain noise

Diagnostic procedure

STEP	INSPECTION	RESULTS	ACTION
1	Is a squealing, click or chirping sound present?	Yes	Inspect the following: • Engine oil level • Solenoid valves installation • Drive belt tension • Generator installation • Splash shield or under cover looseness • Auto tensioner bearing damaged 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 following: • Drive belt tension (See DRIVE BELT INSPECTION [MZR 1.8, MZR 2.0, MZR 2.5].) • Loose parts in engine compartment ― If there is any malfunction: • 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: • Intake air system leakage • Spark plug looseness • Vacuum 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 • Exhaust system • Intake air 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 1.8, MZR 2.0, MZR 2.5].)
6	Is a knocking noise present?	No	If noise comes from engine internal: • Inspect the following: ― Friction gear ― Timing chain ― Tappet noise ― Valve clearance ― Variable tumble control system operation ― Balancer unit backlash (MZR 2.5) ― Variable valve timing control actuator (MZR 2.0, MZR 2.5) • Repair or replace the malfunctioning part according to the inspection results.
7	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 1.8, MZR 2.0, MZR 2.5].) • If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis. ― If the vehicle is repaired, troubleshooting is completed. ― If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.