Step  | Action  | Yes  | No  | 
|---|---|---|---|
1  | Is a light tapping sound heard from the engine?  | Go to Step 2  | System OK  | 
2  | Inspect the valve springs. Are the springs weak or broken?  | Go to Step 3  | |
3  | Inspect the valves. Are the valves sticking or warped?  | Go to Step 4  | |
4  | Inspect the valve lifters. Are the valve lifters dirty, stuck, or worn?  | Go to Step 5  | |
5  | Inspect the camshaft lobes. Are the camshaft lobes damaged or improperly machined?  | Go to Step 6  | |
6  | Inspect the oil supply to the valve train. Is the oil supply insufficient or poor?  | Go to Step 7  | |
7  | Inspect the valve guides. Are the valve guides worn?  | Go to Step 8  | |
8  | Inspect the valve spring seat. Is the valve spring seat incorrect?  | System OK  |