15,000 mile oil change

[skeet]

Quite a few years ago I sold Amsoil products. The oil was good for 50,000 miles. I did change the filter every 5000 miles and put an oil additive in at 12,500 though. I was running the oil (plus transmission oil and rear grease) in a Datsun pickup. I even had the oil analysis done, like they do for aircraft engines. Had virtually no metallic particles in the oil. Put 90,000 miles on it before I sold it. It rusted apart before the engine quit. Guy had 340,000 miles on it when he took it off the road. never had any problem with the engine. He continued using the synthetic in it. In it's lifetime it had 9 complete oil changes and 3 of those were regular oils. You know, until about 1958, all cars didn't have oil filters. That was part of the reason for oil changes at 2,000 and 3,000 miles. Remember the Kendall oil sign with 2 fingers held up for oil changes at 2000 miles? I do change the oil every 5,000 in my wife's Diesel Jetta and it uses synthetic....at 5 bucks a quart!