Engine Noise

DETECTION CONDITION AND POSSIBLE CAUSE

18	ENGINE NOISE
DESCRIPTION	Engine noise from under hood

ENGINE NOISE INSPECTION

STEP	INSPECTION		ACTION
1	CHECK FOR NOISE Attempt to identify/isolate the source of the noise. Possible sources of noise could include: Vacuum or exhaust system leaks. Loose components. Secondary ignition arcing. Base engine components. Intake air leaks. Drive belts or related components. Has the source of the noise been found?	Yes	If concern is obvious, service as required. If not, go to step 2.
1		No	Attempt to get more information about the symptom. If unable to verify symptom, See DIAGNOSTIC INDEX to service any additional symptoms.
2	CHECK FOR "SNAP" SOUND THAT MAY BE DUE TO SECONDARY IGNITION ARCING? Is the noise a "snap" sound?	Yes	Check ignition system. See TEST 17: IGNITION SCOPE TEST .
2		No	Go to step 3.
3	CHECK FOR "SPARK KNOCK" NOISE? Is the noise "spark knock"?	Yes	See KNOCKING / PINGING .
3	CHECK FOR "SPARK KNOCK" NOISE? Is the noise "spark knock"?	No	Go to step 4.
4	Verify test results. If OK, See DIAGNOSTIC INDEX to service any additional symptoms