Knocks on Start-Up but Only Lasts a Few Seconds. Opel Sintra 1997

For 1990-2009 cars

The following conditions may produce engine knocks on initial startup, but only last a few seconds:

• | Improper oil viscosity

- | Install proper oil viscosity for expected temperatures.

- | Refer to Maintenance and Lubrication.

• | Hydraulic lifter bleed down

- | Clean, test and replace hydraulic lifter, as necessary.

- | When the engine is off, some valves will open. Spring pressure against the lifters will tend to bleed the lifter down. Repair the lifter only if the problem is consistent.

- | Engines operated for only short periods between startups may have lifter noise that lasts for a few minutes. This is a normal condition.

• | Excessive crankshaft end clearance--replace the crankshaft thrust bearing.

• | Excessive front main bearing clearance--replace the worn components.

• | Timing chain tensioner malfunction--clean and inspect the timing chain tensioner. Replace the timing chain tensioner, if required.