POSSIBLE CAUSES
1. High or low oil level in crankcase
2. Thin or diluted oil
3. Low oil pressure
4. Dirt in tappets/lash adjusters
5. Bent push rod(s)
6. Worn rocker arms
7. Worn tappets/lash adjusters
8. Worn valve guides
9. Excessive runout of valve seats or valve faces
CORRECTION
1. Check for correct oil level. Adjust oil level by draining or adding as needed
2. Change oil. (Refer to 9 – ENGINE/LUBRICATION/OIL – STANDARD PROCEDURE)
3. Check engine oil level. If ok, Perform oil pressure test. (Refer to 9 ENGINE/LUBRICATION – DIAGNOSIS ANDย ย ย ย ย TESTING) for engine oil pressure test! specifications
4. Clean/replace hydraulic tappets/lash adjusters
5. Install new push rods
6. Inspect oil supply to rocker arms and replace worn arms as needed
7. Install new hydraulic tappets/lash adjusters
8. Inspect all valve guides and replace as necessary
9. Grind valves and seats