Hi, I was hoping to get some technical view point on the correct oil to run in the 5.3 L v-8. In the hope of enjoying improved fuel economy, cooler running temps and longer engine life, I recently changed from Dino based oil to a full synthetic (Mobil 1), same wt (5w-30). While speaking with a gentlemen at a recent fuel stop he suggested that I might benefit from such an oil change after a few thousand miles of "wear-in". I was under the impression that all engines coming out of the factory are already seated and due to modern materials, don't need the same "break-in" as they did years ago.

Anyone care to comment ?? Thank you, Andy

I've been using Mobil 1 Synthetic since day one.
I did not need to go through a "break-in" period.

Thank you for the input >>>Andy

I'm using Mobil1 5w-30 in my '05 Envoy Denali. Works for me.

here mobile 1 is 0w-40 they dont sell 5w-40 i wish they had i,ll be the first one to use 0w-40 so light maybe for vette guys as its recommanded by manf

I'm continuously using Mobil 1 for several years, I might say it increases performance of my engine.. "Mobil 1 lubricants have given us performance advantages of between 3 percent and 5 percent, demonstrating, in a very practical way, the excellent gains of working with ExxonMobil."

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