I've been off the forum for a while and did not have the time to read all of the previous posts. Has anyone mentioned that there is a TSB (SI B 11 09 07
September 2009 - Intermittent Hydraulic Valve Adjuster (HVA) Noise) on this issue which says it is covered under the warranty. Unfortunately I got persuaded that it was "normal" before the TSB came out, and I didn't find out about the TSB until after my warranty ran out. I should have known better. It was clearly a lifter sound (while it may seem hard to believe, adjusting lifters is something we did years ago to solve this issue).
A series of marathon swims to raise money for the American Foundation for Suicide Prevention