Diesel power

[Tboy]

Hey everyone! I'm new to the RV Forum and need some real life experience with Deisel engine oil change and service intervals. I have a 07 Revolution LE 40E, with Spartan MM Chassis and a 400HP C9 CAT and Allison 3000 tranny. I bought the coach used in 2013 with 49,000 miles on it with all fluids replaced at that time. In the fall of 2015 I had the oil analyzed with about 12,000 miles on it and the oil was still within specs and good to go for a bit longer. Despite this, I had all of the hoses, belts and fluids changed on the engine, transmission and the Onan diesel generator in January of 2016. Not a cheap job to say the least, but I expect to keep this rig for a while.

I currently have just over 8,000 miles on the oil, so it's well within the 15,000 mile oil change interval, however, it's the same oil from the 2016 service. Do any of you anticipate a problem with not changing the oil over a 2-3 year period, even when the miles are well below the recommended oil change interval? I check the oil before every use and it's always at the full mark.

Also, what other components should I change or check on the engine to keep it running as expected?

I live in south louisiana and store the rig inside and enclosed storage unit, so there are no huge temperature swings during the year. By the way, we did get down to 12 degrees this past winter!

Thanks for whatever words of wisdom or advice you can offer.

 

[Gary RV_Wizard]

The engine manufacturers recommend oil changes based on time as well as mileage simply because they have no way to know if the oil has become contaminated by moisture condensation, fuel or exhaust leaking past the piston rings, or whatever.  If you have the oil analyzed and can verify it's condition, there is no need to change it. Filters can still be dirty, but that interval can be stretched out too if you are confident enough.  For most owners, though, regular changes simply eliminates any worry. On a diesel, though, the cost of the oil and filters may be high enough to make the cost of n oil analysis worthwhile. Probably is if you pay a shop to do it, but a DIY oil & filter change is much less expensive.

On my '04 American Tradition, I always changed the engine oil & filter annually (DIY).  I would probably change the oil filter regardless and an oil analysis would be another $30, so the $100 DIY cost of the full change seemed reasonable.  For the Allison tranny, I came to the opposite conclusion. The tranny fluid change is quite expensive vs the analysis and in motorhome use the odds are the synthetic tranny fluid will last for 10 years or more, so testing made more sense than arbitrary changes.

The genset oil & filter change is trivial in cost and effort either if you DIY. 

Somebody will surely come along and ask why you are being an oil cheapskate when your $30,000 engine is at risk if you are wrong.  Whether you buy that or not depends on your attitude toward risk.  Do you ever jaywalk? Drink water from a hose? If not, maybe you should be changing your oil annually.