#
NO.21 ENGINE NOISE [L8, LF, L3]

id0103a1802700

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)
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
No | Go to the next step.
3 | Is a rattling noise present? | Yes | Inspect rattling location for loose parts.
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
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
No | Go to the next step.
6 | Is a knocking noise present? | Yes | Go to symptom troubleshooting "No.11 Knocking/pinging". (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [L8, LF, L3].)
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 ENGINE SYMPTOM TROUBLESHOOTING [L8, LF, L3].) - 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 [L8, LF, L3].)