I change my oil to royal purple and ever sence have been hearing a pretty bad tic coming from my pasanger side head I know about piston slap but that makes a lower pitch deeper nock than a valve. This sounds like its just below the heads all the way in front. This sound does not go away when the engine heats up... but does get quieter. When I rev the engine I hear it most when rpm's are coming back down below 2000. sounds like something is coming apart in there. Is this likely an a car with only 25k on it? Or do you think I just have a very bad case of the slap? Thanks