See link: http://www.rislone.com/winter.htm
I bought and used some of this, but now am thinking it is a waste of money, because at best it is basic sythetic, perhaps with a slug of extra pour point depressants. So with a good group II oil like Valvoline Maxlife that has some synthetic (12-22%) it seems you already have the "winter start" condition and if so desired, likely could do as well as the Rislone product, by adding a half quart of Valvoline Syntec oil to top up.
I bought and used some of this, but now am thinking it is a waste of money, because at best it is basic sythetic, perhaps with a slug of extra pour point depressants. So with a good group II oil like Valvoline Maxlife that has some synthetic (12-22%) it seems you already have the "winter start" condition and if so desired, likely could do as well as the Rislone product, by adding a half quart of Valvoline Syntec oil to top up.