For the Cummins, what is the best brand of synthetic lubricants? Redline-Lucas-Royal Purple or Amsoil or ?

 

these questions always result in loaded soap box answers of everyones fav oils. Any 15w40 for summer and 5w40 for winter oil will do just fine. These engines will run well over a million miles with just simple oil changes with $2 a quart dyno oil, the engine normally out lasts the truck when left stock. The brand of oil I run in my Bike and quad raceing engines that get up to 400F in the tight woods @10,000RPM do require the very best, and I run Amsoil for those engines

 

joem that is a very good answer. we run a fleet of dodges, some have at or over 1,000,000 miles on them with 15w-40 dello. never been into any of them

 

A good and inexpensive synthetic is Rotella 5W-40. Walmart has it for under 20 bucks/gallon.

 

287,641 miles on my bombed '95 and I've always run plain old Rotella 15W40. I expect it to last at least another 287,000 miles or so and I'll stick with Rotella.

 

almost 800,000 miles on rotella 15-40 too. But I do use Amsoil in the automatics they seem to hold up better under abuse .

 

I run Amsoil in mine, engine, trans, transfer case, front and rear diffs, air filter, heck, even run it in both of my welders, wifes vehicle and once I replace the engine in my second welding truck I'll load it up with Amsoil.

That's just me though. What you think is the best might not be what I think. Sure it's a bit more but when they say 25,000 mile oil changes they are miles ahead of everybody else. I do my wifes vehicle once a year. Every March I change the oil and forget about it. No window stickers, no forgotten changes, just once a year, easy.

 

22 diesel engines on all the farm trucks, tractors and equiptment.
15w40 Delo in all of them for 40 plus years.

 

i did run 15w40 delo for a a long time, then for some reason at our local wally world (cheapest place in town for oil) they swithced the delo to the sythetic blend delo, so i swithced to rotella triple protection 15w40. im a big fan

 

What's the difference between 15w40 and 5w40?

 

Viscosity.

Us cold climate folks pretty much need a thinner viscosity for the -40F months.

Saying that, i currently run 5w40 all year round but do minimal towing........for now.

 

So in warmer climates, like BC coast, a 15w40 should be fine all year around?

 

Yup, if you don't get much below -10C than 15w40 should be just fine.

 

Yup everyone is correct, Amsoil is indeed the best ( my father was one of the first dealers back in 1978 as he was in the US airforce with AL ) but honestly the cummins will out last the truck and still run great when pulled and placed in another truck and most likely out last that truck as well. If I could see into the future It will need sleeves and pistions/berrings when its placed into that 2025 F350 that the previous owner blew up and sold you cheap decades from now

 

............I run 0W40 synthetic year round....I do lots of towing........kim..