OIL ADVICE / AND ISSUE

[WRS4]

Ok my first question is what oil can someone recommend please?

I currently use edge 5w and i think its 30, but im often seeing 5w 40 is a better choice especially if there's any slight noises such as chains ect which leads me onto my next question.

I have developed what i can only describe as a rattle, there is no noise when the engine is running, and i cant always hear the noise but its usually when im accelerating ? so would 5w 40 help combat this issue? and any ideas what this issue maybe just for future reference encase i need to get it repaired

i am happy to move over to a completely new oil if that helps my situation so any advice welcome