Hello. This is my first post here. Im a new user but have frequently visited the site before. Anyway,syn or conventional? The car is a 2004 toyota camry 3.3 v6. Up until now the car has has been serviced every 5k by toyota. Now with almost 80k ill be doing it. I know that the main reasoning for most using syn is extended oci. I just like the fact that syn keeps an engine cleaner, and leaves behind less buildup. Lasting longer is an added bonus. With conventional 3k oci would be fine, but would it leave behind more buidup than syn. I would prob stay at 5k oci on syn. At 80k is syn even a good idea? I know the history of the v6 mz engine being prone to sludge and want to keep her as clean as possible.