Thanks for the info on my last question.

Checked with the filter manufacturer and have it in writing that the Kralinator has a anti drain back valve in it. Had the dealer listen to the engine this afternoon as I was away for a couple of days and it hadn't been run. He just scratched his head and said - " don't have any idea what that was". The rattle only lasted for about 1 second and then was gone. He did say that he has heard it in 5.4s but didn't know what it is. So agian, if anyone knows any more - let me know. I don't need this thing getting worse.