If you are used to petrol engines, it's quite disconcerting to find that the oil in diesel engines turns black almost immediately. On my V6 the oil would be black after just a couple of miles.
As above. my first diesel car was a Vx Omega Elite which at the time was fitted with a straight 6 diesel from BMW , I was shocked at the oil colour change and the fact that it burned oil , which all though normal on these engines was a first to me.
It's not that the engine produces soot almost instantly to darken the oil. The residue of old oil in the engine contains soot with a particle sizes as small as 1 micron. It's an extremely efficient dye which blackens the new oil very quickly. A new filter doesn't help as the soot particles would have to be 20 times larger for there to be any chance of the oil filter catching them.
Thanks for the reply folks, yes I am used to petrol engines where the oil will normally stay golden for a few months - depending on use ofcourse.
I was just a bit concerned it had gone black so quickly !