Difference between oil weight Options

[hs2g]

I was wondering what the differences are in the oil weight. Like 10w40, 10w30, 5w30 you get the picture. What do these numbers represent? And since I live in minnesota I hear running a lower weight is better durring the winter season?

BTW what oils does everyone use? I would use synthetic buy they are too pricey for me, so i'm using Valvoline Maxlife.

[97GTinKC]

I wish everyone would realize that unless you have rebuilt the motor and prepped it for racing with looser clearances, you need the weight recommended in the owners manual.
Using a heavier oil can actually harm your car. it takes more horsepower to pump. it takes longer to get oil to everywhere in the mornings, it can cause your oil press relief in the filter to be operating all the time, thus NOT be filtering your oil,,, these are the main reasons you should stick with the 5w30 recommended in the book for MOST All driving conditions....and a multi-viscosity oil doesnt actually get thicker when its hot, it protects like an equivalent single weight oil at higher temps.
I have went to using the Amsoil series 2000 0W30 full synthetic, it works GREAT, oil light goes out instantly, no probs in hot or cold weather. recently did a trip to Dallas and Houston from KC, had some stretches where even the slow lane was cruising 85+ (2 hours at 4100 rpm!) 1500 miles round trip, used almost a half pint in 1500 miles of hard driving...