I was at AutoZone yesterday, was playing with the little oiled gear display they have, where you crank one compared to the other to see the difference between the 2 oils. The clerk had to go to the back for something, so to amuse myself, I kept playing, and playing, and playing with it, but noticed no difference between them, other than the one stuck to the plastic gears better.

When he came out, I said, I've been turning this thing like crazy, but don't notice any difference. He said, you're not supposed to. The oils both feel alike, but one lasts a lot longer, and it works in gas or diesels.

I called the company, Lucas, to check his story out. They said their 15/40 "Magnum" Long Drain Truck Oil can be used in cars, and will last a MINIMUM of 15,000, without breaking down, due to it's high TB Number, but I forget what TB stands for. He said you could actually go 20,000 miles, but they cap it off at 15,000. Said you'll be perfectly safe doing that. I think he alluded to the thing that they have some way for you to test it along the way so you can see for yourself that it's still protecting your car. Check 'em out on the web for more info.

Rotella has been highly recommended by a lot of you dieselers out there, but if I can go a whole year on one oil change, guess what I'm doing? Mind you, the stuff is $6 per quart, but it's less work and less expensive in the long run.

...and now an update since the original post, above which was written a few months ago. I contact Lucas this week, talked to a different person, got a different answer. He says Lucan Long Drain Oil will help give you about another 1,000 miles on an oil change, and most importantly, protects your engine from cold starts where it's just metal against metal. He says it will make a big difference in life of the engine.

jeff
1991 300d, 90k