15w 40 Motor Oil

Lou I have used rotella 15w - 40 in all of my older cats and other makes.
I am careful about putting any detergent oil an old engine that has used non detergent oil for many years. The newer oils keep the dirt and crud in susspension with the oil where the older non detergent oils left it settle out. Therefore when you put the new oils in the old engine it will bring a lot of the crud out from hiding and may clog the screens and filters. So I use the 15w-40 after an engine is rebuilt or completley cleaned inside. Ron Meeder

I buy it by the 55 gallon drum. I also use it in everything I own, new and old. When putting it in an older tractor I sometimes fill the crankcase with diesel fuel and run for a minute or two and then drain. I the refill with motor oil and a new filter. Never had trouble yet. My Toyota corolla knocks for a few seconds when the temperature gets in the single numbers and I now use 5-30 in that during the winter and change over in the summer. It just seems easier than having to buy different kinds of oil.

Brian

I've occasionally used the Rotella 15w40 but only when I couldn't get the straight 40 weight Rotella. Works well in the old Cats and my Detroits too, but as mentioned just need to watch for junk getting loose and clogging filters/screens and such. If you have a discount club like Sam's or Costco they usually have it by the 55 gallon drum for a good price.

😞 I tried 15/40 shell rotella T in my fresh rebuilt D8- after bout year it started building up yick on the valve guides in pony-[did the same thing to 392 chrysler hemi in pickup] so got nervous in big eng- switched to mobile full synthitic 10/40 for high millage eng's-{regular full syn seems to go through valve guides etc @ an alarming rate- while the stuff for high millage engs doesn't} seems to be a better oil -specially since for last year or so? most of additives in oil have been taken out which protect cam & lifters-[thanks gov- same for sulpher etc that made diesel what it was] theory being the full synthetic might keep cam & lifter in better shape -[first clue of problem-- local racing engines started losing cam/ lifters as soon as oil changed]

They took all the zinc out of the oil. Good old STP is mostly zinc. I started adding a bottle to all my flat tappet cammed engines.

Better do a little homework....STP is mostly mineral oil....contains 1-5% zinc dialkyl dithiophosphate. (check MSDS). The diesel engine oils still contain adequate quantities of zinc (Shell Rotella included).

I don't see the need for the fancy multi weight oils in these old engines. There is nothing in them to utilize the light end viscosities like the hydraulic lifters in gasoline engines unless your running in very cold climates. I run straight 30wt in everything I have, 40wt is also a good option if running in hot climate.

[quote="Old Magnet"]
I don't see the need for the fancy multi weight oils in these old engines. There is nothing in them to utilize the light end viscosities like the hydraulic lifters in gasoline engines unless your running in very cold climates.[/quote]

But is there any thing detrimental about using multi weight oil in the old engines? I buy 15W40 for my modern ag tractors by the 250 gallons. I use it in my old graders because its what I have on hand. Anything wrong with that?

No, I don't believe any harm will be done.....might be a little higher consumption though.