When you review the Mobil 1 product guide it lists Mobil 1 EP and High mileage as "Boosted, advanced full synthetic formula". Does this mean that M1 High Mileage is as good as Extended Performance?? I always thought the ranking order (as far as how good the oil is) was Mobil Super Synthetic, Mobil 1 regular syn, M1 High Mileage, Mobil 1 EP then the new AP.
I basically was using EP exclusively then just started using High Mileage M1 and was wanting to know if I am "going backwards" in overall performance. I know the oil will be fine for my 6-7k mile OCI's but I just want to hear from anyone in the know if M1 HM is as stout as EP.
Car is 2008 CTS 3.6DI
https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-oil-product-specs-guide.pdf
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