Im a big fan of running heavy duty diesel type oils in my quads and motorcycles.....I usually buy either Rotella T, Chevron Delo or Mobil Delvac - depending on which is cheapest.

Im not here to debate if its good oil or not....just to inform of a change that some may not be aware of.

As of the last batch of oil I bought (I usually buy LOTS at once so I dont buy often....so this may NOT be new news) the Shell Rotella T 15w40 and Rotella T6 fully synthetic 5w40 both carry the JASO-MA certification on the bottle.

Personally I had years of experience with the oil so the certification doesnt mean much to me....but now it is "certified" for use in motorcycle/atv.

 

15W sounds kinda thick for cold starts. The first number is for cold starts viscosity ONLY the second Number is for operational temperature viscosity.

So a 0W-40 with flow alot quicker, easier and thinner on cold starts then 15W-40 but when both oils are warmed up they have the same 40 viscosity.

Not sure what advantage having 15W "honey thick" like oil on cold starts would be? Get the oil flowing as quickly as possible is my thinking.

The "second" number is the most important,thats the viscosity the motor will have when running at its hottest.

Thats why 0w-40 is one of the most popular Synthetic grades, it will flow great in the coldest Arctic temps on start up and run all day in the hottest deserts. It just cover the entire temp range you can ever encounter.

 

glad somebody understands that concept. I've been arguing with people about the viscosity numbers for years. My buddy just bought a truck with 160k on it and on someones advice switched to Rotella 15w40. Tried to tell him it was too thick for cold starts. Motor blew up this weekend. Coincidence? Perhaps. I run Rotella 15w40 in my diesel, but sometimes in the winter if its bitter cold Ill run 10w40 in it.
I use 0w40 in my atvs. simply cant imagine why you would want to punish the engine with 15w cold oil. Just because it still works doesnt mean its ideal.

 

Then buy the Rotella in the 5w40 weight then.....I dont see where I recommended any weight for any application or temperature.

Some people dont ride in the winter either and dont concern themselves with starting their ATV under such conditions.

 

I agree, the diesel oils are a great bang for the buck in atv/motorcycle engines. They don't have the friction modifiers that kill a wet clutch early, are able to handle high compression and combustion contaminates, and still take care of that high rpm turbo as well.