C 8.3 Mechanical Oil Change Interval?

[jd956jd956]

Greetings! I have a '97 American Eagle with the purely mechanical C 8.3 Cummins with approx 65k miles that I purchased with 55k miles. I have done two oil analysis tests and both came back a-ok. One right after I bought it and one recently. The first test was with the oil that came in it and the most recent was a sample that had 2,200 miles on the oil. I probably should have waited until I had at least 3k miles on that oil and I might not be asking this question, but here goes. I have been changing it every three thousand miles but believe I am probably throwing good money away. The Fleetwood book says change every 5k miles while the green Cummins engine manual says change every 6k miles. Any thoughts / suggestions on what would be "best" for this older engine? Thank you in advance! Jeff...

[sc3283]

Jeff, if you run the engine the majority of the time where it is allowed to warm up completely...you can run those change figures up. If your primarily really short trips and or do a lot of 5-10 minute run times (ie: to move the coach around) especially in colder weather, then your probably doing the best as you are.
With 16-20+ qts of oil in these motors, it takes a good 20 miles at highway speed to get oil hot enough to burn off contaminants. Even more in winter months.
I bought mine 1 yr ago...it had almost 3k on the oil. I changed it because I did everything to have a starting point for my own maintenance. I have 3k on this oil and it is just starting to turn black(as all diesels do). It will stay in a couple thousand more

[deandec]

Everybody has a theory or opinion on oil changes. Here is mine.

Cummins says 6 months or 6,000 miles oil change whichever is first to maintain the warranty.

But that was in 1995 when oils and filters were less developed.

The guidance was for an "average" group of Cummins owners across a broad spectrum of uses.

The guidance was "seasoned" by the Financial Department and Legal Department respecting warranty exposure and so has a reasonably conservative cushion built in.

The Cummins manual says something about variances in frequency accompanied by oil testing, but I do not have it immediately available to quote exactly.

If the oil still has the capacity to absorb and store the contaminants (via oil analysis) then I am inclined to run past the 6 month/6000 mile guidance.

But, to calm a prospective buyer of my rig, I change the oil and filters once per year and keep the records.

[FormerBoater]

I'm with Deandec on the annual cycle for my trusty C8.3.

Usually I have put 6-8K on during the year. The 3 oil analysis all told me that I did not need to change the oil, but as I use Speedco for this service and it is very reasonable in cost I am fine with the annual service.

I do believe in a chassis lube every six months as per Spartan's recommendation

DaveS
1998 American Eagle 40EVS
Cummins C8.3 325 HP

[RobRV]

I change My Engine Oil and Filter once a Year. The Fuel Filters and Coolant Filter are changed at the same time. The Chassis gets Lubed as well. We put about 6000 Miles on her each Year .Mostly on One Long Winter Trip from BC to Mexico and Return.

It Is a 1998 DSDP with Cummins C8.3 and Alison 6 Speed on a Spartan Chassis.

Just rolled over 50,000 Miles.

[Shadow0120]

We had a 1996 8.3 and I had it changed every 6000 mi that was at the end of the year just before I put it in winter storage that way it was ready to go in the spring.

[NHRA225]

1992 American Eagle 8.3 C Service intervals.
5000 Miles
Change Oil (Lucas 15/40)and All Filters (Fleetgard) and Air Cleaner- Chassis Lube = (Speedco)
10,000 Miles - Diff Oil Change- (Speedco)
50,000 Miles- Full Allison Service- Transend- Both Filters