Got 18K out of my last Mobil 1 oil change. Had it analyzed, and the results were noral, but change was recommended. I had a 79 LTD that I got 300K miles out of before the body decided to quit living, and ran Castrol Dino in it. One time I went 30K between changes with just adding oil, mainly because I never had time to change the oil, or when I did, the weather wasnt cooperative, but when I removed the engine from the defucnt body to put into another car, I had to replace the pan with the correct one so I inspected the engine while I had it apart, and the results were the engine was almost like new, there was no noticable wear, the only thing that determined wear was the plastigauge showed ~.003 difference from when the bearings were initially installed. It was an engine I had blue printed myself.
Moral of the story, use good oil, good filters, they dont need to be synthetic, and you don't have to change it every 3000 miles like Jiffy lube would want you to with their marketing hype. In fact there was an article on MSN about saving money and the first thing on the list was the 3000 mile myth.
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