@Burla are you saying you would run 0w30 over 5w20 for the winter?
No, I said that as a compromise because you didn't want to run 20 weight. We seam to be choosing our oil based on what we hear, me included, and some oils make the hemi sound better. If I had a loud knock at start up I would at least try 0w20 first, assuming the cause of thickness, some knocks need moly to sound better. Because these two knocks showed up when it got cold, this is the strategy we are considering, and it does make sense. Because as hemi users and owners oil strategies are all we really got for these ******** FCA tolerances. You could even attempt to fix this mechanically and have the same issue when you are done, it's just our reality. So I would try and solve it with lubrication and give it the best chance first, and if cold is the issue then 0w20 is the best chance at being the thinnest at startup and have same operating visc as 5w20. Now, when I say thinner at start up mind you we are talking about potential viscosities in the 100's if not 1,000's, so it's not thin by any means, just made for cold temps.
Additionally, we have had knocks, like mine severe, but 5w20 ended the knocking, and 5w30 also has had no knocking. But some trucks 5w20 didn't stop knocking, it took 5w30. Here's the thing, you don't know where your truck falls unless you try 0w20. If 0w20 keeps cold knock away, and also keeps hemi tick away as in warm idle knock, then clearly that would be the way to go imo. Mind you if our strategy is not working, we have to adjust. I'm spoiled it was 80f two days ago and 77f yesterday. So I don't know how my truck would be reacting in the cold, just that any oil is thicker in the cold.
My opinion, if there isn't an oil that can keep both away, cold idle knock and warm idle knock, clearly the choice would be whatever works against warm idle knock, as that is a disaster. Bottom line, time for you guys to experiment, I wouldn't be afraid of trying twenty weight oil if it can kill both warm and cold ticks. There is no guarantees, but this is best guess stuff. 0w20 will let you know if this can be solved with oil, there is no thinner at cold temps, again it isn't thinner oil at operating temps, just thinner at start up.