Because if you bother to send your 3k mile oil to the lab it will come back like new and still good for service. 8k-10k is very doable in most engines, even city driven ones. Modern engines are very easy on there oil, they don't really put as many combustions by products in it. Its been shown on the diesel forum that you can run 6k-8k miles on quality synthetic oil in a 603. If you can do that with a 603 I don't see why say 10k-13k miles would be out of the queston for a modern engine.


Most of this is just hear say. Lab's don't lie. Send your oil out to the lab and see what they say. If it comes back good for service at 3k miles why not extend to say 5k? Why spend the extra money for no gain?

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200