Just work it out yourself from the numbers on the oil.Eg:20W-50 etc.The first number,20W is how thin ,or how easy the oil will flow at cold startup,the lower this number is, the easier the oil will flow or pump when cold.The thinner the oil is at cold startup,the better the protection, as it gets through the oil pump,into the oil galleries and to the bearings etc a lot quicker than a thicker oil would.Remember,90% of engine wear occurs at cold startup.The last number represents how thick the oil will stay when its hot.The higher this number is,the thicker the oil will be at high temperatures or hard running etc.Usually a 20W-50 oil will be fine.I use a 15W-60 oil which exceeds the recommended oil specifications,it is a bit thinner at cold startup than the recommended 20W-50 stuff ,but it also stays thicker than the 20W-50 oil at high temps.Years ago they only had monograde oil,and you had to run thinner oil in the winter time,and then change to a thicker oil for the summer time..then they came out with multigrade oil.The "W" in front of the first number stands for winter, and obviously shows the oils cold rating.Basically,you want the thinnest oil possible at cold startup,but then you want it to be as thick as possible at high temps for maximum protection.Synthetic oils are usually the best at this.