How often to change oil with a synthetic blend?

[311Hemi]

Last oil change put syn blend rotella in the F350 and rather than running 10K miles on conventional may go to 15K miles. 193K miles

The F250 runs Amsoil and gets new fluid every 25K miles. 294K miles.

The Excursion runs Rotela syn and new fluid every 20K miles. 222K miles.

All are 7.3 and never had any motor work...

Have you had your oil analyzed when using those intervals? Why the different oils in different vehicles?

I just got my oil analysis back on my 2500 Cummins and the Rotella looked good after 5700 miles (6 months). I usually run it to 7500 miles but I like to change at least twice a year....so I did it early this time. Not driving as much now. Might just have to run it out to 7500 miles and get it check, and maybe more if that looks good.

[Jeremy airjer W]

How much does it cost to have the oil analyzed?

[311Hemi]

$15 from Cummins NPower. I had never done it before and wanted to check it, so at least I have a baseline for in the future in case of any fuel injector issues or coolant leaks. Their report gave me levels of certain wear metals and contaminates, fuel, glycol, TBN, visc@100 levels. My report said that all engine wear rates are normal and the analysis indicates proper performance of the lube and unit.

I think it's around $25 from a company called Blackstone that a lot of guys use on the diesel forums. I think it may be a little more detailed than the Cummins one and will actually tell you if they recommend an oil change or if continued use is fine.

[mechanico]

Hey Hemi,

Tell me more about this NPower please

[CigarGuy]

I have a new f150 (gas) and it has a synthetic blend. Paperwork I got with the truck says every 7500 miles. In fact, I talked to the dealership today asked about the first oil change and they still say 7500.

[Crm7290]

I use synthetic in my 08 Rabbit and after 30,000 miles of every 5000 I was told to only change it at 10,000. It balances out to being about the same price as regular this way.

[311Hemi]

Hey Hemi,

Tell me more about this NPower please

Cummins NPower is just the name for the Cummins shops here in the midwest I believe. They are just one company that offers the oil analysis service.....along with parts and service for Cummins engines....etc.

You can stop into one of their shops and buy the oil analysis kit and then send it in to them. They will send you back a report.

If you want more information I would go to the Backstone Labs HSOforum, they are another company that offers this service. They will tell you if you can run your oil longer or not. The Cummins service does not, it just tells you if it is still meeting the proper protection levels.