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100-04-40 Noise, Vibration and Harshness 100-04-40 DIAGNOSIS AND TESTING (Continued) PINPOINT TEST E : DRUMMING NOISE Test Step Result / Action to Take E1 CHECK THE EXHAUST SYSTEM Key in START position. Yes CARRY OUT Exhaust System Neutralizing in Increase the engine rpm until the noise is the loudest. Note the engine this section. TEST the system for normal rpm. operation. Key in OFF position. No Add approximately 9 kg (20 lb) of weight to the exhaust system. Place Go to E2. the weight at the tailpipe and test. Key in START position. Increase the engine rpm and listen for the drumming noise. Note the Key in OFF position. Using a vibration analyzer, determine the amount of vibration that Is the noise/vibration reduced or eliminated, or does the E2 POWERTRAIN/DRIVETRAIN MOUNT NEUTRALIZING Carry out Powertrain/Drivetrain Mount Neutralizing in this section. Yes Test the system for normal operation. Vehicle is OK. TEST the system for normal Is the noise reduced or eliminated? No CONDUCT diagnosis of other suspect PINPOINT TEST F : ENGINE TICKING, KNOCKING OR CONTINUOUS RATTLE Test Step Result / Action to Take F1 CHECK FOR NOISE AT THE VALVE COVERS AND THE FRONT COVERS (OHC ENGINES) Carry out the Vehicle Cold Soak Procedure in this section. Yes REMOVE the appropriate cover and INSPECT Key in START position. for loose, worn/broken components. REPAIR as NOTE: For a short-duration ticking noise, multiple engine starts may operation. be necessary. No Using an EngineEAR, listen closely at the valve covers and the front Go to F2. covers by placing the probe near the surface of the valve cover and Key in OFF position. Is the noise source apparent? F2 CHECK FOR NOISE AT THE CYLINDER BLOCK Key in START position. Yes REPAIR or INSTALL new components as Using an EngineEAR, listen closely at the cylinder block by placing a necessary. probe on or near each freeze plug. No Key in OFF position. Go to F3. Is the noise source apparent? G72679 en |