Ready to switch to Synthetic....miles between changes????

[DHerzog]

I think I have decided to switch to Royal Purple synthetic 15w40 in my 2004. 5 Cummins...



I've been using Mobil Delvac 15w40 and have no complaints, and have been changing at about 4,000 miles.



I was anticipating longer drain intervals with Royal Purple, but to 10,000... is that realistic?



Thanks for you comments.

 

[mberry]

10,000 mile changes is what I do with my Amsoil. I don't know why it would be any different with any quality synthetic oil.

 

[67guzzler]

I thought our owner's manuals state the light duty cycle calls for oil changes at 15,000 miles on the 2004. 5 and the 2005's and the heavy duty cycle calls for oil changes at 7500 miles. If my memory serves me correctly -- this was with regular motor oil, not synthetic..... If I'm right, going to 10,000 miles with syn should be a snap.

 

[mberry]

You are correct Jay. The problem is that almost no-one can drive in the conditions required consistently enough for the 15K mile change schedule.

 

[Kurt Henzler]

i am using amsoil 15w40 and changing the oil filter only at 7500 then both oil and filter at 15,000. done this twice sent oil to analysis after 15,000 with good numbers. it even said "no service needed at this time". silicon levels were 4 and 6 with scotty 3.

 

[cyborg]

I'm doing RP, change oil, filter and fuel filter (they're cheap) at 10k.