il filters are rated by their Beta Ratio. This is a test where the filters are subjected to a fluid and the fluid is loaded with very specific amounts of known glass beads. The size of the glass beads are a known as well as how many. Sizes can vary to 1 micron. The fluid is then run thru the filter. What the filter captures is known as its single pass specs. A decent filter will capture around 90% single pass. Your K&N won't pass that test. After the results of the single pass test, then the fluid is pumped thru the filter over and over until there are no glass beads being filtered out. This is called multi-pass specs. That's how K&N designs and tests their filters. Here's the good news, I think the test critieria is pure BS. There is no set spec for the viscosity of the fluid, no set temperature, no set pressure or rate that the fluid is pumped. But there is a test. When looking at any oil filter, know you are looking at compromise of some kind. You can have great flow, like the K&N, or you can have great filtration, like a Purolator One, but you can't have both. If you have a filter media that filters great, it will sacrifice flow to get it. To get great flow, you'll sacrifice filtration. Synthetic media, blended media, or paper, doesn't matter. Most any quality oil filter will go 10,000 miles easily on a current production engine. With our gasolines we have today and the lean burn technologies, the engines just don't make the trash they did when you had a carbed engine. Of the better oil filters, Purolator and the NAPA Gold are about as good as it gets for filtration. Mobil One and K&N are among the best filters for increased flow.
About the oil. While you don't the issue, there are some here probably driving a direct injected engine. They are a problem child. For your truck and those that have the DI engines, you need to know what NOACK is. It is the amount of oil that evaporated under the ASTM D-5800 test. The oil is subjected to heat of 250C/ 482F for one hour. The number given to the test is the amount of oil that will cook off or evaporate in percentage of weight. So when you have the Mobil One 5w-30 at 10.2, that means that 10.2% of the oil by weight cooked off. The maximum allowable by API is 15%. Not much "premium" in the bottle in my opinion. You can do significantly better by switching to the cheaper Pennzoil Yellow Bottle in 10W-30, which has a NOACK of 4.2 and beats ALL synthetics by a lot. Note, this is 10w, not 5w. If your cold startup temps never get to -25C, you can use the 10w oils. If it gets colder, you'll need to stick with the 5W or even the 0W oils. So my recommendation is to use the Pennzoil YB in 10w-30 unless you have the minus 25C and colder startups. The 2.5 Nissan engine is used a lot in testing motor oils. A simple engine that wears great. The Platinum is a good choice. The 2.5 at 7500 miles should be no issue. The 4.0, I'd suggest 6000miles instead regardless of what oil you use. The issue is the 4.0 engine likes to shear oil. 7500 miles will be pushing it to the max. As an oil shears, it gets thin and it starts to degrade. I'd call 6000 miles tops.
