Changed the oil in my NA a week or so ago and my lifters began to rattle. the rattle went away mostly after about twenty seconds but was still noticeable. Did some googling about lifter noises and came up with an interesting GM bulletin. Not solstice specific but pertaining to their four cylinder engines in general. Over filling the crankcase beyond the max (mine was over the max) level will allow the crankshaft to contact the oil in the crankcase causing it to froth. These tiny air bubbles in the frothy oil will find their way into the lifters and, since air is compressible, will cause lifter rattle. Removed about 1/2 qt. of oil and the rattle is gone!! Even on startup! Most of you guys probably already knew this. I didn't.