I suppose it all depends on how clean you expect oil to be in a diesel.
When I got my 1.6HDi it had a bit of a dodgy service history, so I dropped the sump to see if there was a sludge problem, with the sump off I was able to make a good job of cleaning it out. The oil was truly black.
Below is a picture of the oil 350 mile after the sump removal - I would suggest this looks very clean for oil in a diesel. And demonstrates how much your new oil is contaminated by what does not drain out of the sump in a normal oil change.
[Image: 33aylfq.jpg]
When I got my 1.6HDi it had a bit of a dodgy service history, so I dropped the sump to see if there was a sludge problem, with the sump off I was able to make a good job of cleaning it out. The oil was truly black.
Below is a picture of the oil 350 mile after the sump removal - I would suggest this looks very clean for oil in a diesel. And demonstrates how much your new oil is contaminated by what does not drain out of the sump in a normal oil change.
[Image: 33aylfq.jpg]