If it's the Lash adjuster leaking down and not holding like the seal so the oil pressure stays in then the thicker oil will help that. The difference in noise-masking ability from the 5w20 a 10w30 is not a whole lot. Also, the detergent additives like MMO will flush out a small Speck of dirt or a sticking plunger or seal inside a lifter or so the noise might go away