my car has had nothing but mobil 1 in it since it was new....12 year and 180K miles ago. Compression is extreamly good in it still. I just got a leak in the oil pan gasket, but that isn't the oils fault. I did just switch to AmsOil, the good 25K mile or one year interval stuff. If you want to save money get that stuff. $5.35 a quart and get a filter that lasts 12K miles for another $10. Costs $45ish but then you don't have to worry too much for a year....besides doing the filter.
