rvrepairnut wrote:

2008 425 cummins ISL the book says 200000 miles.I dont beleive in the or once a year theory.You could easly go 2 years 12000 miles on the isc.Book on that is 15000 miles

racerchaser wrote:

Something to think about. I have no problem with any of the above information. Everyone has an opinion and that is fine with me as it is your money not mine. However, there are some points you might keep in mind.
If you store your coach during the year and change oil once a year it is best to do it before you put the unit in storage. The reasoning is that if you do not change it before storage all of the impurities that have been gathered by the oil during the year just sit there and work on the engine surfaces during the storage period. You should treat any internal combustion engine in this manner be it auto, motor coach, lawn mower, etc. Regardless of any analysis, oil that has been used for a period of time will not be as "lint free" as new oil.
Owners will spend thousands of dollars on add-ons (supp braking systems, TPMS, etc.) and go to great lengths to save a few dollars on oil.
It is a DP. It is like a boat or airplane. It costs money to own.

rvrepairnut wrote:

2008 425 cummins ISL the book says 200000 miles.I dont beleive in the or once a year theory.You could easly go 2 years 12000 miles on the isc.Book on that is 15000 miles

PHE wrote:



Well, on the ISC Cummings says


Routine Maintenance Recommendations
Check oil level daily.
Oil Drain Interval Fleetguard Filter
15,000 miles / 12 months LF 9009 (all ISC models)
and about oil analysis

Oil Analysis
Oil analysis, as a method to extend drain intervals, is NOT
recommended. Different methods of measuring soot, lack of
correlation among testing labs, and differing driving patterns
and idle time are the basis of the recommendation.

From:
http://cumminsengines.com/assets/pdf/4971287.pdf

phe