I do not want this to turn into "what kind/brand of oil to use" thread, but I do have questions on the weight of oil.
I currently use Shell Rotella T6 Synthetic in the 5W-40 weight.

I own 2 570’s and they have an engine "knock" at idle (always have). Not bad, but they both have always bothered me.

If I used a heavier weight of oil would that quiet them down? What is considered "heavier" as I do not understand the numbers in oil.

OR….. do I just live with the knock?