At 30000 miles I using Rotella 15/40, changed at 5000 miles, after that oil change I now use Rotella 5/40 full syn, change at 7500, fuel and air filters at 15000, trans service at 30000, easy to remember.

 

I try for 5k, usually get it done around 5.5k but have gone as long as 7.5k. I just can't imagine what happens at the end of the oil change interval that would make a significant difference between 5k and say 6k. The only good way after warranty considerations are over is to do oil analysis since driving styles and conditions are probably just as important as mileage.

 

The Cummins engineers who designed and built it, the company that warranties it and the dealer that sells it all say 7500-15,000. I go by what those who know the most reccomend backed up by independent oil anyalisis. I would rather hang on to my $ than give it to the Iranians or big oil unnecessarily.
Joe

 

The only ones I can see doing 5K oil changes are those who do 75% or more stop and go city driving other then that I see lot of money and good oil going to waste. As mule3010 said I would trust what Cummins has to say and not a SM at a dealership who gets a cut of all the money they save the company each month screwing us.

 

I'm going 10K between oil changes with an oil sample at every change. Also change the filter every 5K.

 

I went 5K of the first couple then switched to syn. The book says to switch to 5W40 for Syn. Not sure why, but I'll go the 12k or 15K at least now.

 

First 4 oil changes were at 4500miles. Now at 18000 I've switched to Amsoil and will change about every 7500miles.

 

Why? With a schedule like that you would not see any benefits by running a very expensive full synthetic. The conventional oil would still maintain most if not all it's lube/suspension qualities at that kind of mileage. If you are towing near max cap., in town only, in hot temps you would still just be approaching the recommended change interval for conventional oil.(as determined by the engineers that designed/built the engine).
Joe

 

Approximately every 6K miles which means it get changed 4-5 times a year. Of course the dealer puts 3K intervals on the window sticker when they change it.

 

10k miles is generally when I try to change it. Sometimes a bit over, sometimes under.

 

Around 7k, or when I get time.

 

Was thinking my first change would be at 10,000 but if the fuel filter recommendation is at 15,000 I'll wait a little longer and get them done at the same time.

For the first few oil and fuel filter changes it will go to the dealer... Most catastophic breakage occurs earily if it is a faulty part and I don't want any questions as to it...

 

Every 3500 to 5000 miles with synthetic Mobil 1. I change my fuel filter every other oil change. I do lots of city driving and mountain towing in dusty conditions.

I don't care about bypass systems and OA, thats overkill to me and a waste of time. I just change my oil and roll on. Who cares how much it cost? If I had to have cheap oil changes I would have bought a Geo Metro. I'm not going to pay 45k for a truck and then skimp on a $50 oil change every 3 or 4 months by trying to see how far I can stretch out the intervals.

 

Hey Joe T, I'd consider changing that fuel filter before 15,000 miles. I do mine at 7500 miles and it's usually pretty dirty.

 

Cool, I was hoping someone would answer that question... You just talked me back into my 10K interval.