15,000 Mile Oil Change Interval

I run 7500 mile intervals on my 11 3500 Cummins. When I delete all the crap off it I may go to 10k. The oil now gets contaminated with fuel by the 7500 miles. I know a few people in my trade with trucks using Amsoil bypass filtration and go up to 40K miles on the oil with filter changes every so often with oil analysis.

 

We do 5k oil changes on everything. amsoil 0/20 in the cars/suv's, amsoil 5/30 in the tractor, and my powerstroke and 460 powered dump truck gets delvac(tried rotella and cant keep up with adding oil when running it and I am too big of cheap skate to run amsoil in a 300k mile truck ). I have debated going further with the oil changes but we do so many short trips and the trucks get worked hard with lots of idle time so i have stayed with the short oil changes.

friend of mine ran amsoil signature series oil in his car and had oil analysis done after 20k miles...oil was still good so he just changes the oil once a year no matter how many miles he puts on.

 

How much does a Blackstone UOA go for? I am on an annual plan with most of our vehicles running synthetic.... Without UOA I'd be hesitant to push more than annually, not to mention I do see a mileage drop right around oil change time.

 

My favorite oil story is my dad's old 92 Civic. He bought it from a co-worker who put 100,000 on it in 2 years (he was an over-the-road salesman), and had all the maintenance done regularly at the dealership. My dad, who isn't the best with maintenance, changed the oil with regular dino oil about twice a year which came to an oil change roughly every 20,000 miles. The first thing to die was the transmission at 280,000 miles, but he found a used transmission/engine combo with less miles so he switched both out. I sometimes wish he'd have left the original engine in there because I was curious how long that engine would last with the maintenance "abuse" it was given. He had that car until it hit 340,000 miles when parts where regularly starting to fail.

As to me, I typically do 7500 mile changes running full synthetics from either Pennsoil, Valvolene, Quaker, or Mobil depending on what I find cheapest. I always use WIX filters. I'm a little more "matured" now and don't hit the redline in my car and truck as often as I used to, so I'm considering moving to 10,000 oil change intervals.

 

How often do you clean your air filter? On my truck, I have a cotton filter that doesn't require oil. But my car came with a K&N, but I use the oil recharge very sparingly!

 

If you use the Toyota synthetics you will be fine. Still have to check the oil level frequently and keep it up from time to time.

You might be ok going 10k but maybe not. Miles themselves are not what we should be concerned with when using good quality synthetic. Keep in mind some synthetic is only marginally better than dino oil as it is the additive package not the base stocks that make up the cost of the oil. As far as the severity of the demands placed on the motor the factor usually overlooked is the hours. Amsoil has suggested 350 plus or minus a few hours as a benchmark for oil changes. So all highway at 70 mph average is 25,000 miles. But a taxi in Arizona sitting idling with the air conditioner running 70% of the time might have only have 7500 miles between changes. In both cases the oil would be in about the same condition. Cold winter starts are tough on motors even with a synthetic that has a pour point of minus 40F. Not all synthetics are created equal. The best we can do is use the best and change as per the manufacturers suggestions or 6 months. We will always run into people who know more than the engineers that designed the motors but keep the salt shaker handy.

 

I normally change oil every 5000 miles or when I run out of bar oil. Which ever comes first.

 

good one! pass the salt please! lol

 

You did it now all the tree huggers are going to accuse you of polluting the environment with used oil

 

That's all taken into account. 90% of my driving is highway in my car. My car sits in a heated garage at home, and a parking garage at work where the first few minutes after a cold startup in the evening are basically me coasting down 7 stories to the street level. On the other hand, I only put a few thousand miles a year on my truck, and those miles are spent hauling or towing things or quick trips to the hardware store, so it get's a yearly oil change regardless of the miles.

 

I agree it is not a given, which is why I don't fly blind on assumptions, but rather base my long intervals on the results of credible analysis.

No serendipity here . . . unless that was the name of the technical writer at Toyota who typed up the 7,500 mile change interval recommendation in the manual.

It's not a matter of one gambling and paying for the analysis as you say, but really choosing one or the other if increased intervals is in the plan. I am paying for occasional reports, but I am not gambling at all. I'll pit science against opinion any day.

 

You can do your own research, but the last I checked synthetic oil has no expiration date. I've very safely gone 18 months with zero issues and my next oil change will likely be closer to 2 years.

 

I think I just paid $28 for the analysis and an additional $10 for the TBN test. I don't know what TBN stands for, but it's the additional test you get if you are interested in longer change intervals.

 

Under normal conditions I recharge it at 10k miles but I check it very frequently and if it's getting dirtier faster than normal I'll drop that down to 8k. I'm generous with the recharge oil...

 

change back to factory air filters, K&N are notorious for letting dirt thru. check some diesel sites for info on them. 3000 mile oil changes are from 50 years ago, with the advances in oil technology your oil changes are well in line. there are a lot of truck people that do oil analysis, get results and change the filter and keep going. oil does not wear out, it gets contaminated from "stuff" in the engine as you see from your oil analysis. i run 10000 between changes on my Cummins and do not even think about it, i know guys that go 20-25 with oil analysis.

 

Some of the reasoning behind 1 year is the assumption of a lot of short trips on the engine, which could lead to fuel contamination because you never reach full operating temperature. i forget the figure but it takes X time to circulate all the oil from the pan thru the motor and filter it is longer than you think

 

I did switch back to a factory filter this time around. It was a tough call though; as they mention in the report, the silicon is up, but after several thousand miles like that it has shown no appreciable detriment to the engine internals. I'll miss the K&N, but at the very least it'll be shelved for the next 18-24 months...

 

I bought a 2013 Chevy Cruze to drive to work and back. It will go about 7800 miles before it says the oil life is at 0%.