NO.21 ENGINE NOISE [YF (2.0L Zetec)]


21	ENGINE NOISE
DESCRIPTION	Engine noise from under hood
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) 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 sound noise: • Dynamic dumper looseness • Exhaust system looseness • Intake-air system looseness Other noise: • Camshaft friction gear noise or MLA noise • Timing belt noise


STEP	INSPECTION	RESULTS	ACTION
1	Is a squealing, click or chirping sound present?	Yes	Inspect for the following: • Improper engine oil level • Improper drive belt tension • Splash shield or under cover looseness • Generator installation (alignment)
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 and P/S fluid level.
2	Is a rumbling or grinding sound present?	No	Go to the next step.
3	Is a rattling sound present?	Yes	Inspect rattling location for loose parts.
3	Is a rattling sound present?	No	Go to the next step.
4	Is a hissing sound present?	Yes	Inspect for the following: • Vacuum leakage • Spark plug looseness • Intake-air system leakage
4	Is a hissing sound present?	No	Go to the next step.
5	Is a rapping or roaring sound present?	Yes	Inspect the following for looseness: • Dynamic damper • Intake-air system • Exhaust system
5	Is a rapping or roaring sound present?	No	Go to the next step.
6	Is a knocking sound present?	Yes	Go to symptom troubleshooting "No.11 Knocking/pinging". (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [YF (2.0L Zetec)].)
6	Is a knocking sound present?	No	If the noise comes from inside the engine, inspect for friction gear, timing belt, or MLA noise.
7	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [YF (2.0L Zetec)].) • If any malfunction remains, inspect related service information and, repair or diagnosis accordingly. - If the vehicle is repaired, troubleshooting completed. - If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [YF (2.0L Zetec)].)