Hi guys i have a 90 vaux cav gsi ! there is nothing wrong with the car..exept the engine is just sounding...well...lets say its been driven HARD!! and its a tad noisy! not the old tappets noisy but just wear and tear i guess !! there is pleanty of oil in the old beast..so i was just wondering ( and i know i have posted something similular few months back) if there is anything i can add to quiten the old dog down IE: anything to add to the oil?