engine oil change interval ?

The 2004 owners manual diesel supplement INFERS that oil changes could be as infrequent as every 10,000 miles, or more if the "life system" doesn't indicate a need.
This seems high for a hard working engine, but this is my first diesel....
Other forum threads suggest as frequently as 4,000 miles, and doubly confusing some guys change oil+filter at 8,000 with a filter-only change at 4,000.
Seems backwards to me; if you were going to do one thing only, surely the oil twice as often as the filter, no?
thoughts welcome and appreciated, thx.

I run Mobil Delvac 1 5w40 synthetic and work on 10k change intervals. I could and can go further yet, but 10k has worked well particularly on my 2012 which is changed on the 10's.

Note: I may have to add a bit between changes which is plenty acceptable. I haven't tracked this well, but it's less than 1qt and the stick never gets below the add mark.

For a diesel engine, oil life is dictated more by soot concentration than by mileage. These clean diesels produce very little soot in the tailpipe, and very little soot makes its way past the rings and into the engine oil. As a consequence, drain intervals have increased considerably.

Back in the 1990s, diesels weren't as clean burning, and they sooted up the oil much faster. This is where the recommendation for a 3k-4K mile drain interval began. The oil in those engines darkened very soon after a change. Soot is abrasive, and the oil was changed largely to reduce the soot.

Jim

thx,
however proving I'm a diesel nube, is an '04 considered a"clean diesel"?

(I know the fuel I buy today is, but does engine influence this?)
thanks

Quote:

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Originally Posted by Ian7

thx,
however proving I'm a diesel nube, is an '04 considered a"clean diesel"?

(I know the fuel I buy today is, but does engine influence this?)
thanks

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In 2004, it was. Now, no.

Maybe swap "clean" with "modern high pressure" which began for GM with the introduction of the first Dmax.

Modern high-pressure common-rail diesel fuel injection is a big reason why today's diesels are cleaner. Engines today are also cleaner because of better engine design and current emissions control systems.