Thor Forums

[TurnerFam]

our diesel has certainly been changed several times in 6 years and over 107,000 miles, but whether I do it 'exactly' at 15-20,000 miles, or whether I do it at least once 'yearly' really is a matter of feel... some might worry and fret that somehow 'suddenly' the engine is going to give out, give up the ghost, and go 'south', just because you went 1 mile over the 15,000 mile 'suggested' change cycle, or 1 day over the 'suggested' time change - it's not going to happen.
As someone else mentioned, the 'oil' is not going bad, it's just been flowing in your system when you travel, and sitting when you're not - no worries. Unless you have extensive off-roading in your travels, it's doubtful that most any 'RV' diesel gets anywhere NEAR the usage and potential debris that any commercial over-the-road diesel would get, with many using this same engine - an ISB6.7L Cummins.

Like most owners, I've changed my filters many times, and probably more often than really 'needed'.

I think the 'time' concern is much less worrisome than the 'mileage', since mileage is due to usage, where the engine and oil is actually interacting. When sitting, nothing is happening - the oil doesn't care.

Of course, as a matter of advice, and probably leaning more toward very, very conservative numbers, filter manufacturers are going to give you time frames and mileage that reflects that - whether it really applies to you and your usage, or not. Plus, it provides more opportunities for you to purchase their products. Oil shops are the same, of course they are going to side on the edge of 'better safe than sorry, listen and go exactly by the manufacturer's info', whether it's really warranted, or not....