Oils and Numbers

Wayne
"We all know the difference between a XD9000 and a TX3400"

No - I don't !
I use Valvoline Gold 20/50. It has a moderate level of detergent - this keeps the dirt from the moving parts - I think oil for diesel motors have a higher detergent level?

My understanding is -
The Nos. refer to the viscosity or stickyness of the oil at different temperatures - if we lived in Antarctica we may use a No 10 oil?
The letters after - SG/SI etc refer to the SAE (engineers) standard that the oil meets.

A quick Google search gave me too much data - but this may help.

"Engines need oil that is thin enough for cold starts, and thick enough when the engine is hot. Since oil gets thinner when heated, and thicker when cooled, most of us use what are called multi-grade, or multi-viscosity oils. These oils meet SAE specifications for the low temperature requirements of a light oil and the high temperature requirements of a heavy oil. You will hear them referred to as multi-viscosity, all-season and all-weather oils. An example is a 10W-30 which is commonly found in stores."

"We all know the difference between a XD9000 and a TX3400"

Hey Wayne, do you copy? I'm a bit stuck and the XD9000 is on the blink - can you give me a pull out!

Do I have it right????

Wayne,
I think that the W is "weight", as in viscocity, in the industry we refer to an oil as a 32 weight or a 10 weight I may be way off but that seems to fit, the CH and the GL codes refer to international standards so there is some comparrison, when I was asking Nissan about which oil the only concern was use oil that met the standard, brand didn't really come into it. That's why some companies say as long as it meets the "meets and exceeds the standard. Hope I'm right.

Wayne,
If you don't find a satisfactory answer or you want to hear it rather than read it BP have a good lubes line that will answer all your queries. When I'd been through the process I then got it in writing from Nissan that what I'm using is ok and doesn't effect the warranty, just because of all the issues with the 3.0 litre turbo. I use the bp Vanellus C6 plus which I've confirmed is ok, not as easy to find as the standard bp Vanellus C6. And yes I am affiliated, sorry but someone has to work there.