5000 miles of hard summer driving including high speed runs through hilly interstate at extra legal speeds at 100F external temperature. 170,000 miles on engine.
Its Valvoline Maxlife Synthetic in 10w-30 (backed by a K&N HP1010 filter)
Why did it resist breakdown to well?
I think the fact that the multiviscosity spread is so small must have a lot to do with it as there must be few if any Viscosity index improvers in this formulation available to break down.
Keeping in mind that this is a high milage oil packed with extra detergents there is another thing this tells me.
The engine is internally sqeaky clean or the detergent package would have pulled more dirt out of the engine into the oil.
And finally this engine clearly has zero blowby and doesnt use a drop of oil (the oils position on dipstick a touch below "full" is the same after it was filled)
If this wasnt a Nissan engine one would have to suspect a recent engine replacement had taken place, right before I bought it 5 months ago.
But its the original engine.
Just goes to show how good Nissans really are.