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TAPPETS-HYDRAULIC ROLLER DIAGNOSIS AND TESTING - HYDRAULIC TAPPETS Before disassembling any part of the engine to correct tappet noise, check the oil pressure. If vehicle has no oil Check the oil level after the engine reaches normal operating temperature. Allow 5 minutes to stabilize oil level, OIL LEVEL HIGH If oil level is above the FULL mark, it is possible for the connecting rods to dip into the oil. With the engine running, LOW Low oil level may allow oil pump to take in air. When air is fed to the tappets, they lose length, which allows valves TAPPET NOISE DIAGNOSIS 1. To determine source of tappet noise, crank over engine with cylinder head covers removed. 2. Feel each valve spring or rocker arm to detect noisy tappet. The noisy tappet will cause the affected spring and/or rocker arm to vibrate or feel rough in operation. NOTE: Worn valve guides or cocked springs are sometimes mistaken for noisy tappets. If such is the case, 3. Valve tappet noise ranges from light noise to a heavy click. A light noise is usually caused by excessive leak- down around the unit plunger, or by the plunger partially sticking in the tappet body cylinder. The tappet should 4. The valve train generates a noise very much like a light tappet noise during normal operation. Care must be taken to ensure that tappets are making the noise. If more than one tappet seems to be noisy, it’s probably not REMOVAL 1. Disconnect the negative cable from the battery. 2. Remove the air cleaner (Refer to 9 - ENGINE/AIR INTAKE SYSTEM - REMOVAL). 3. Remove intake manifold (Refer to 9 - ENGINE/MANIFOLDS/INTAKE MANIFOLD - REMOVAL). 4. Remove cylinder head cover (Refer to 9 - ENGINE/CYLINDER HEAD/CYLINDER HEAD COVER(S) - REMOVAL). 5. Remove rocker arm assembly and push rods (Refer to 9 - ENGINE/CYLINDER HEAD/ROCKER ARM / ADJUSTER ASSY - REMOVAL). Identify push rods to ensure installation in original location. HB ENGINE - 5.7L SERVICE INFORMATION 9 - 1411 |