I have owned several vehicles over the years and with every one of them the oil would turn black within some time. With my current 07 T/C the oil pretty much stays the golden brown color through the 5,000 miles, there is a slight difference in the color towards the end of the interval but defiantly not black by any means. I am guessing that the prior owner did some regular flushes or something, the engine seems to be very clean especially on the outside. Had this van since 11/19/12 with little over 95,000 and was very pleased with how clean everything was. I am at 108,000 now and loving this van.

 

Prolly more to do with - you get what you pay for -S-synth / F-synth, your service diligence, and the fact that these beasts run pretty cool compared to many. Congratulations on 108,000, and still loving it !

 

The quality of the oil sure makes some difference in how quick the oil turns black is also my experience.
But there is also a huge difference between diesel and gasoline, in my Mercedes 2.3 E I use very good semi synth and at the oil refresh @ 20K km it still looks almost new.
But in my diesel I use good full synth and it gets black slowly after like 10K km.. Other diesels I owned previously did the same Oil in diesels gets blackened quicker it seems.

 

That's right, the soot production from diesel combustion is much more than is petrol and manufacturers are always trying to get it down to meet legislation. The soot particulates are also laced with other unburned hydrocarbons which is the real danger, not the soot itself. Since the diesel has a very high compression and is (virtually) never throttled, the blow-by between pistons/rings and cylinder wall is much more and ends up in the sump oil. Good quality diesel engine oil keeps the soot in suspension, so it goes black.
There is the inevitable diesel trade-off between soot and NOX. You can easily make a diesel to produce practically no soot, trouble is, the NOX output goes up sharply. So the latest diesels tend toward a compression ratio of 16:1, a bit lower than the ideal soot-burning 18:1, simply because of less NOX with the lower temps. Hence so many DPF filters now.
The best engine for low pollution? A high-compression petrol engine running on propane, LPG. The carbon-monoxide at idle is so low it's hard to measure, and the soot is so low you can leave synthetic engine oil in the sump for 20,000mile. The carbon dioxide output in normal running is 45% LESS than that engine/car combo running on petrol. And if your compression ratio is either 10.5: 1 or pref. higher, the micro. plus knock sensor automatically sets the spark timing well advanced for efficiency. LPG will work good in an engine with 12:1 ratio. This ratio with petrol would require 5-star -- totally illegal now. But 5-star was well known in 1970s US to power the Boss Mustangs et al with super-high ratios.

Our VM-Motori diesels are very understressed at only 150horse. Other manufacturers are getting this horsepower out of 1.9 diesels. So you don't have to rev. a GV's head off to get some power. I should think these engines are prime candidates for "chipping" to get more power if that is required, without too much danger of damaging the engine. This understressing is prob. why the engine oil doesn't get black too quickly, and why these engines have such a long service life. ( Economically important if you are running a London taxi...)

Leedsman.

 

Just round the corner from you on Intercity Way lad.

 

As to black engine oil. I once had a Citroen 1.9TGD back a bit, and it still had black oil after an oil change. So as I had barrels of oil to play with at my work, a BR refuelling point, I changed it one day four times and guess what, it didn't take long to go black again without moving the car. Mind you this oil was good for providing clean engine innards, never a bit of carbon inside on strip downs, except around piston rings.