Sorry to bring up this old thread but I wanted to thank Woody for the great info. The car has been ticking from the front of the passenger side cylinder bank at cold start up (e.g. after sitting for 9 hours). The ticking was fairly loud to begin with and would rise with revs but would quiet and go away as the engine warmed up. I should have looked into the issue awhile ago but did not. Finally searched the forum, saw Woody's posting on the O-rings and said WTF - let me try changing them. At cold start up the ticking is now much quieter and goes away after 7-10 seconds. Waldig I owe you a beer or a diet coke your choice.