No I am not sure that the oil caused the failure, but I just stated my experience and opinion. I said "I say its like everything else they sell. Made cheaper for them so they can undercut the price" this is known fact look it up its there business model. Lastly if you don't think that manufacturers make cheaper quality products for big box stores then you are misinformed. I don't want to debate Wall Mart just stating my experience. I buy my oil from from an oil distributor. It's about a 40 mile round trip but I only go there once a year. I get 15w40 Citgo in 5 gal buckets for about $30. I have been running this oil since 1987 when I bought my first 1987 6.9 new. I sold it with 300,000 miles in 2000 and its still running today.