Will thinner oil reduce cold start rattle?

[MikenOH]

When I switched to 15W-50 last year, my first start out of hibernation went ok but after it warmed, I had the ticking associated with a flat lifter.

I've changed to Syntec 10W40 and have not noise at all either at start up of after on the road for an hour. I have to say that using Syntec has seems to have gotten rid of all the ticking or metallic noises coming from the engine.