Need a bit of advise I have a 01 japanese import wrx. I live in a pretty hot country. Changed the oil recently using full synthetic mobil 1 10w/30 oil, however I notice now since the oil change that occasiionally on a cold start up I would hear a strange clacking sound which then goes away in a few secs. My mechanic advised that I should put in something thicker than what I have currently as it might be the simms on the car. Can anyone shed some light, any similar problems.