NO.21 ENGINE NOISE [MZI-3.7]

id0103d2802700

21 | ENGINE NOISE
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DESCRIPTION | • Engine noise from under bonnet.
POSSIBLE CAUSE | Squeal, click or chirp noise: • Improper engine oil level • Improper drive belt tension • Auto tensioner bearing malfunction • Improper installation of purge solenoid valve • 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 • Variable valve timing actuator malfunction Other noise: • Camshaft friction gear noise or tappet noise • Timing chain noise

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | Is a squealing, click or chirping sound present? | Yes | Inspect for the followings: • Engine oil level • Drive belt tension • Purge solenoid valve installation • Auto tensioner bearing damaged • Splash shield or under cover looseness • Generator installation (alignment) Repair or replace the malfunctioning part according to the inspection results.
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 Repair or replace the malfunctioning part according to the inspection results.
No | Go to the next step.
3 | Is a rattling noise present? | Yes | Inspect rattling location for loose parts. Repair or replace the malfunctioning part according to the inspection results.
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 Repair or replace the malfunctioning part according to the inspection results.
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 Repair or replace the malfunctioning part according to the inspection results.
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 [MZI-3.7].)
No | Inspect for followings: • Valve clearance (See VALVE CLEARANCE INSPECTION/ADJUSTMENT [MZI-3.7].) • Variable valve timing actuator Repair or replace the malfunctioning part according to the inspection results. • If there are normal, noise comes from the engine internal, inspect for friction gear, timing chain or tappet 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].)