Oil Change intervals??

In a nutshell, everyone has to live within their comfort level. That same applies to car owners that still stick with 2000-3000 mile oil changes. Hardly necessary, but that is what they can feel comfortable about. I only take issue that short oil change intervals are positive proof of a long running engine. I can use my own example of an N-14 going to 1.5 mil on 30,000 mile oil changes and still running great and never an oil related problem. But that is not any kind of positive proof one way or the other. There have been studies done, most recently by Chevron, that show engine internals looking great on 400,000 - 500,000 mile engines with oil changes as high as 70,000 miles. Now, I have to admit, that is outside even my comfort level. But the case study is what it is. I have a tough time with the studies that show 300,000 or more on a complete oil change when one is using a bypass filtration system. But I have no real evidence that they are wrong. And some of those engines have been opened up, at the cost of the company doing the study, and have shown excellent internals. Oil samples are solid evidence of what is going on and what condition the oil is in. And anyone relying on any kind of extended drain has to do regular oil sampling. To do otherwise is foolish. And some of the oil samples I have seen from various testing labs have shown soot levels as low as .3 on oil that has been in the engine for 100,000 miles on those engines that are using bypass filtration. The viscosity is still in range for the oil, and the TBN package is still good. Again, not in my comfort level, but it is proof that oils can hold up for a long, long time and do the job. Engine oils have come a long way since we were kids. That is one of the reasons that the OEM's have increased their drain interval recommendations over the years.

 

I change mine every 15,000 unless I have little to no idle time then I will go to 20,000

 

Believe it or not I do longer intervals on my Cummins powered Ram and our Altima than I do the big truck. The altima has Amsoil synthetic and filter in/on it and you'll cringe when I say I change it every 15,000 when Amsoil says 25,000 would be fine. Who knows maybe we will just let it go to 25,000 this time why not, I know it's good oil. A quality synthetic is really convienient and cost effective in a car. I never did 3,000 mile intervals in any car or pickup, I always did 5,000 but it doesn;t take long to turn 5,000 miles and it feels like you're changing the oil all the time. That is why synthetic goes into the car so we only have to change it once a year if that... The Ram gets 15,000 mile intervals, or 1 year whichever comes first, with Rotella. There is just something I can't wrap my thoughts around to the idea of going to longer intervals on my big truck. I do not have a bypass filter. It is my bread and butter "vehicle". I know it is expensive and know full well the "science" behind longer intervals that says they are ok.. I just do it the way I continue to do it because that's how I like doing it. No-one will ever convince me to do otherwise, it's just how I prefer it done.

 

I change every 500hrs, mileage means nothing.