5w-40 oil

[JFP in PA]

Originally Posted by achillies

What is the reason to not use 0w-40 Mobil 1? Getting ready to change my oil and that is what I have used. Thanks

Simple: There was a time with M1 products were some of the best, but ever since Exxon acquired Mobil, it has been all down hill. UOA's have continued to show products like their 0W-40 going downhill, falling out of grade much sooner than the original products, loss of film strength, low TBN values after short mileage use, etc. The 0W-40 has also undergone multiple reformulations, none of which made it better; and in fact one actually caused it to totally lose its ACEA performance ratings, which it literally barely got back after yet another reformulation. Since Exxon acquired the product line, it has looked more like a product line run by accountants than engineers.

There are simply multiple better products out there, many of which show the ability to hold their performance advantages long after M1 has given it up.