I recently purchased a 2001 camaro z28 6 speed, much fun. It was nearing an oil change and i wasn't sure what the previous was running, and from what i read German Castrol 0w-30 was the best. since the oil change its been making quite a bit more noise, i cant tell if its piston slap or lifters. its also making this really high pitched sound at idle from somewhere in the engine bay. Any tips would be appreciated!