My 2000 suburban has a ticking/knocking noise at startup, and lasts for 30 seconds +-. I have talked to several others with similar problem. It seems to affect higher mileage vehicles more, but my neighbor has a silverado with only 70,000 on it and it has started to tick also. I am certain it is lifters, but have tried different oils to see if it would help. Does not seem to help. I am currently using 10/30 oil and have considered going heavier. Has anyone experienced similar problems and what have you done to eliminate the problem?

 

Most likely have one or more lifters that are draining down overnite and it takes a few seconds for the oil pressure to pump them back up.