Tap tap tap,
Since I did my first oil change (using 10-40w )I've noticed that my tappets are noticeable when the engines starts up from cold. The chap who owned the car before me used 'Slick 50' oil treatment.
Should I just stick to using 15-40w grade oil rather than spending £20 on oil additives. Is 'Slick 50' any good or just another fad? Doesn't 'Slick 50' just thicken the oil up?