My '02 ford Explorer with between 240-250k miles on it, will drip oil if I use the factory recommended 5w30 wt oil in it. I got tired of weekly oil checks and adding 1/4-1/2 qt of oil. So I decided to go old school on it. At last change, I used 4 1/2 qts of 10w30, and 1/2 a qt of 20w50 wt in it with a Motor-craft filter. Almost immediately the dripping stopped. The motor has always been quiet, and it still sounds perfect. My battery is almost 3 years old and during the winter, I didn't notice and negative starting effect from using my heavier mixture oil. 6 months ago and no oil has been needed. The possible difference in fuel consumption is not noticeable either. I do not believing using a different brand of oil , or a slightly different weight of oil will make any positive difference in consumption. Like 5w30 vs 10w30, in the end it still a 30wt. Especially in a used worn motor. Going to 10w40 will make more of a noticeable difference in consumption.,,