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A light tapping noise similar to valve train noise may be caused by the following components: |
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Valve Train Noise |
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Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: A light tapping noise at ½ engine speed, or any varying frequency. | ||||
1 | Is there valve train noise? | -- | Go to Step 2 | System OK |
2 | Check for a high engine oil level. An engine with the engine oil level above the FULL mark allows the crankshaft counterweights to churn the engine oil into foam. When foamy engine oil is pumped into the valve lifters, the valve lifters become noisy. A solid column of engine oil ensures proper valve lifter operation. Is the engine oil level too high? | -- | Go to Step 3 | Go to Step 4 |
3 | Drain the engine oil to the proper level. Is the tapping noise gone? | -- | System OK | Go to Step 6 |
4 | Check for a low engine oil level. An engine with the engine oil level below the ADD mark may allow the oil pump to pump air at high engine RPM. Is the engine oil level too low? | -- | Go to Step 5 | Go to Step 6 |
5 | Add engine oil as required. Is the tapping noise gone? | -- | System OK | Go to Step 6 |
6 | Check for the proper engine oil pressure. Refer to Engine Mechanical Specifications and Oil Pressure Diagnosis and Testing . Is the engine oil pressure within specifications? | 68.65 kPa (10 psi) | Go to Step 11 | Go to Step 7 |
7 | Check the oil pump screen for damage or a loose fit to the oil pump. Is the oil pump screen loose or is the oil pump screen damaged? | -- | Go to Step 8 | Go to Step 9 |
8 | Repair as required. Is the tapping noise gone? | -- | System OK | Go to Step 9 |
9 | Check for a damaged oil pump or loose mounting bolts. Refer to Oil Pump Cleaning and Inspection . Is the oil pump damaged or are the mounting bolts loose? | -- | Go to Step 10 | Go to Step 11 |
10 | Repair as required. Is the tapping noise gone? | -- | System OK | Go to Step 11 |
11 | Remove and inspect the valve lifters, valve rocker arms, and valve pushrods. Refer to Valve Rocker Arm and Push Rod Cleaning and Inspection and Valve Lifters and Guides Cleaning and Inspection . Are the components worn or damaged? | -- | Go to Step 12 | Go to Step 13 |
12 | Replace the components as required. Is the tapping noise gone? | -- | System OK | Go to Step 13 |
13 | Perform a camshaft lobe lift test. Refer to Camshaft and Bearings Cleaning and Inspection . Is the test within Engine Mechanical Specifications ? | -- | Go to Step 15 | Go to Step 14 |
14 | Replace the camshaft and valve lifters. Is the tapping noise gone? | -- | System OK | Go to Step 15 |
15 | Remove the engine front cover and inspect the camshaft timing chain and sprockets for excessive wear or damage. Refer to Camshaft Timing Chain and Sprocket Cleaning and Inspection . Are the components worn or damaged? | -- | Go to Step 17 | Go to Step 16 |
16 | Replace the components as required. Is the tapping noise gone? | -- | System OK | Go to Step 17 |
17 | Perform a complete disassembly of the engine and inspect all components. Are the components worn or damaged? | -- | Go to Step 18 | System OK |
18 | Replace the components as required. Did you complete the worn and damaged component replacement? | -- | System OK | -- |
