NO.21 ENGINE NOISE [MZR 2.0 DISI]

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 installation • Auto tensioner bearing malfunction • Splash shield or under cover looseness (splashed water to drive belt) Rumble or grinding sound noise: • Improper drive belt tension • Loose parts Hiss sound noise: • Vacuum leakage • Loose spark plug • Air leakage from the intake-air system Rattle noise: • Loose parts Rap or roar noise: • Dynamic dumper looseness • Exhaust system looseness • Intake air system looseness • Variable valve timing actuator malfunction • Variable swirl control system malfunction • Improper balancer unit backlash Other noise: • Camshaft friction gear noise • Timing chain noise • Tappet noise Warning The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: • Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. • Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE SERVICE PRECAUTION” and “AFTER SERVICE PRECAUTION” described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.0 DISI].) (See AFTER SERVICE PRECAUTION [MZR 2.0 DISI].) Caution • Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

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 installation

• Auto tensioner bearing malfunction

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

Rumble or grinding sound noise:

• Improper drive belt tension

• Loose parts

Hiss sound noise:

• Vacuum leakage

• Loose spark plug

• Air leakage from the intake-air system

Rattle noise:

• Loose parts

Rap or roar noise:

• Dynamic dumper looseness

• Exhaust system looseness

• Intake air system looseness

• Variable valve timing actuator malfunction

• Variable swirl control system malfunction

• Improper balancer unit backlash

Other noise:

• Camshaft friction gear noise

• Timing chain noise

• Tappet noise

Warning

The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services:

• Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.

• Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE SERVICE PRECAUTION” and “AFTER SERVICE PRECAUTION” described in this manual. (See BEFORE SERVICE PRECAUTION [MZR 2.0 DISI].) (See AFTER SERVICE PRECAUTION [MZR 2.0 DISI].)

Caution

• Disconnecting/connecting the quick release connector without cleaning it may possibly cause damage to the fuel pipe and quick release connector. Always clean the quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

STEP	INSPECTION	RESULTS	ACTION
1	Is squeal, click or chirp sound present?	Yes	Inspect for following: • Engine oil level • Solenoid valves installation • Drive belt tension • Splash shield or under cover looseness • Auto tensioner bearing damaged • Generator installation Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
2	Is rumble or grinding sound present?	Yes	Inspect for following: • Drive belt tension • Loose parts in engine compartment ― If there is any malfunction: • Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
3	Is rattle sound present?	Yes	Inspect the location of rattle for loose parts. Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
4	Is hiss sound present?	Yes	Inspect for following: • Vacuum leakage • Spark plug looseness • Intake-air system leakage Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
5	Is rap or roar sound present?	Yes	Inspect for following: • Exhaust system installation • Intake-air system installation • Dynamic dumper installation Repair or replace the malfunctioning part according to the inspection results.
No	Go to the next step.
6	Is knocking noise present?	Yes	Perform the symptom troubleshooting “NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE”. (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZR 2.0 DISI].)
No	If noise comes from engine internal: • Inspect for following: ― Friction gear ― Timing chain ― Tappet noise ― Valve clearance ― Variable swirl control system operation ― Balancer unit backlash ― Variable valve timing control actuator • 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 DISI].) • If a 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, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI].)

STEP

INSPECTION

RESULTS

ACTION

Is squeal, click or chirp sound present?

Yes

Inspect for following:

• Engine oil level

• Solenoid valves installation

• Drive belt tension

• Splash shield or under cover looseness

• Auto tensioner bearing damaged

• Generator installation

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Is rumble or grinding sound present?

Yes

Inspect for following:

• Drive belt tension

• Loose parts in engine compartment

― If there is any malfunction:

• Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Is rattle sound present?

Yes

Inspect the location of rattle for loose parts.

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Is hiss sound present?

Yes

Inspect for following:

• Vacuum leakage

• Spark plug looseness

• Intake-air system leakage

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Is rap or roar sound present?

Yes

Inspect for following:

• Exhaust system installation

• Intake-air system installation

• Dynamic dumper installation

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Is knocking noise present?

Yes

Perform the symptom troubleshooting “NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE”.

(See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZR 2.0 DISI].)

If noise comes from engine internal:

• Inspect for following:

― Friction gear

― Timing chain

― Tappet noise

― Valve clearance

― Variable swirl control system operation

― Balancer unit backlash

― Variable valve timing control actuator

• Repair or replace the malfunctioning part according to the inspection results.

Verify the test results.

• If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 2.0 DISI].)

• If a 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, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI].)