NO.21 ENGINE NOISE [L8, LF]

id0103a0802700

21

ENGINE NOISE

DESCRIPTION

•  Engine noise from under bonnet.

POSSIBLE CAUSE

Squeal, click or chirp noise:

•  Improper engine oil level

•  Improper drive belt tension

•  Generation installation (alignment)

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

Rumble or grind noise:

•  Improper drive belt tension

•  Improper P/S fluid level

Rattle sound noise:

•  Loose parts

Hiss sound noise:

•  Air leakage from intake-air system

•  Loose spark plug

•  Vacuum leakage

Rap or roar sound noise:

•  Dynamic dumper looseness

•  Exhaust system looseness

•  Intake-air system looseness

Other noise:

•  Camshaft friction gear noise or MLA noise

•  Timing chain noise

•  PCM malfunction

21	ENGINE NOISE
DESCRIPTION	• Engine noise from under bonnet.
POSSIBLE CAUSE	Squeal, click or chirp noise: • Improper engine oil level • Improper drive belt tension • Generation installation (alignment) • Splash shield or under cover looseness (splashed water to drive belts) Rumble or grind noise: • Improper drive belt tension • Improper P/S fluid level Rattle sound noise: • Loose parts Hiss sound noise: • Air leakage from intake-air system • Loose spark plug • Vacuum leakage Rap or roar sound noise: • Dynamic dumper looseness • Exhaust system looseness • Intake-air system looseness Other noise: • Camshaft friction gear noise or MLA 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 • Generator installation (alignment) • Splash shield or under cover looseness 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 sound present?	Yes	Inspect the drive belts or P/S fluid level. (See DRIVE BELT INSPECTION [L8, LF].) Repair or replace the malfunctioning part according to the inspection results.
2	Is a rumbling or grinding sound present?	No	Go to the next step.
3	Is a rattling sound present?	Yes	Inspect the rattling location for loose parts. Repair or replace the malfunctioning part according to the inspection results.
3	Is a rattling sound present?	No	Go to the next step.
4	Is a hissing sound 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 sound present?	No	Go to the next step.
5	Is a rapping or roaring sound present?	Yes	Inspect the looseness for the following: • Dynamic damper • Exhaust system • Intake-air system Repair or replace the malfunctioning part according to the inspection results.
5	Is a rapping or roaring sound present?	No	Go to the next step.
6	Is a knocking sound present?	Yes	Go to the symptom troubleshooting "NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE". (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [L8, LF].)
6	Is a knocking sound present?	No	If the noise comes from the engine internal, inspect for friction gear, timing chain or MLA noise. Repair or replace the malfunctioning part according to the inspection results.
7	Verify test results. • If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [L8, LF].) • If malfunction remains, inspect related Service information perform repair or diagnosis. ― If vehicle repaired, troubleshooting completed. ― If vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [L8, LF].)