Originally Posted By: camrydriver111
I asked this question before and I got two answers: fall and spring.
The argument for fall is the oil has the strongest TBN, and the best cold-performance when it is fresh.
The argument for spring is the oil gets beat up in the winter.
The viscosity is hard to predict, it is possible you will get sheering or dilution, but it is possible to also get thickening. Suspension of combustion byproducts is also supposed to influence cold performance.
I agree with both points, just curious if fresh tbn through winter will be enough for the summer or what's left over after summer will be enough for winter.
Since tbn depletion isnt linear maybe that last couple tbn after summer will be enough for 4 months of winter? Will find out going to due a uoa after my first one year oci, will be starting that oci In March when my change is due