| Table 1: | Momentary Noise On Engine Startup |
| Table 2: | Intermittent Noise at Idle Speed |
| Table 3: | Noise at Slow Idle |
| Table 4: | Lifters Noisy at High Vehicle Speeds, Quiet at Low Speeds |
| Table 5: | Noise at Idle, Becomes Louder at High Engine Speed |
| Table 6: | Valve Noise Regardless of Engine Speed |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: Valve train noise disappears after 1 to 2 minutes | ||||
1 | This condition is normal. Oil drains from the lifters which hold the valves open when the engine is not running. The valve lifter needs a few seconds to fill with oil after you start the engine. Did you allow the valve lifters to fill? | -- | No correction is needed | -- |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: Intermittent noisy on idle only, disappears when engine speed increases | ||||
1 |
Are the valve lifters dirty or damaged? | -- | System OK | |
2 | Replace the valve lifters. Did you complete the valve lifter replacement? | -- | System OK | -- |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: Noisy at slow idle or with hot oil; quiet at higher engine speeds or with cold oil | ||||
1 | Inspect the valve lifter for high lay down rate. Does the valve lifter have a high leakdown rate? | -- | Replace the faulty valve lifter | No correction is needed |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: Lifters noisy at high vehicle speeds, quiet at low speeds | ||||
1 | Check for a high engine oil level. An oil level above the FULL mark allows the crankshaft counterweights to churn the oil into foam. When foam is pumped into the lifters, the lifters become noisy since a solid column of oil ensures proper operation. Is the oil level too high? | -- | Drain the oil to the proper level | |
2 | Check for a low engine oil level. Oil level below the ADD mark allows the oil pump to pump air at high speeds. This causes noisy lifters. Is the oil level too low? | -- | Add oil as required | |
3 | Check the oil pump screen. Is the oil pump screen bent or loose? | -- | Repair as required | System OK |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: Noisy at idle, becoming louder as engine speed increases to 1500 RPM | ||||
1 | This noise is not connected with lifter malfunction. The noise becomes noticeable in the vehicle at 10 to 15 mph "L" (Low) range, or 30 to 35 mph "D" (Drive) range. The noise is described as a "ticking" sound. At slow idle, the sound may be entirely gone or appear as a light ticking noise in one more valves. This noise is caused by one or more of the following:
| -- | Repair as necessary | |
2 | The noise may be an off-square valve spring. Is the valve spring off-square? | -- | -- | |
3 | If the valve spring is more than 1.6 mm (1/16 in) off-square, replace the spring. | -- | -- | -- |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: Valves noisy regardless of engine speed. | ||||
1 | Check for excessive valve lash. To check for valve lash, turn the engine so that the piston in the cylinder is on TDC of the firing stroke. If valve lash is present, Check for a worn valve stem tip. Is the valve stem tip worn? | -- | Replace the valve and any other worn components. | |
2 | Check for a bent valve stem. Is the valve stem bent? | -- | Replace the valve and inspect the guide. | |
3 | Check the lubrication system feed to the lifter and check to see if the lifter is properly lubricated. Is the lifter properly lubricated? | -- | Determine if the oil feed to the lifter or lifter bore is blocked. | |
4 | Check for a worn or damaged lifter or lifter bore. Is the lifter worn or the lifter bore damaged? | -- | Replace the lifter or the camshaft carrier. | |
5 | If the lifter bore appears to be ok and measures to specifications, the lifter is at fault, replace the lifter. | -- | Replace the hydraulic lifter | -- |
