2010 wrangler jku islander edition 3.8 with 144k. Engine has a tick. Only at operating temperature and only below 1500 rpm. I believe it’s a lifter gone bad. Higher rpm increases oil pressure. Looking for thoughts on changing the oil viscosity. Have read run thicker oil to keep the lifter filled. Also read thinner to get the oil to the lifter faster. Anybody have any experience or thoughts. Appreciate the help.