Engine knock has gone away
Thank tou for the suggestion about reving up motor to displace air pocket. It seems to have worked for me after winding out motor to 3000 RPM a few times. I guess I can live with this idiosyncrasy as long as I know the solution and it does no harm to my 6.4 liter...
After my first oil change I noticed some new noises coming from my 6.4.
I brought it to the Ford Dealer who concluded that new noise is totally normal after finding the above service bulletin. It wasn't during the filter cleaning cycle so I was concerned. Anybody else had this experiance?