Knocks on Initial Start-Up But Only Lasts A Few Seconds

- Improper oil viscosity. Install proper oil viscosity for expected temperatures. Refer to Maintenance and Lubrication for engine oil specifications.
- Hydraulic lifter bleed down. Clean, test and replace as necessary.
- When the engine is stopped, some valves will be open. Spring pressure against lifters will tend to bleed lifter down. . Attempts to repair should be made only if the problem is consistent.
- An engine that is operated for only short periods between start-ups may have lifter noise that lasts for a few minutes. This is a normal condition.
- Excessive crankshaft end clearance. Replace crankshaft thrust bearing.
- Excessive front main bearing clearance. Replace worn parts.