It's deja vu all over again.

BMW has had an oil condition sensor in the sump since around 2005. I would be surprised if they deleted it on the diesels. Details here.

http://www.xoutpost.com/696635-post13.html

Edit: Out of interest, I looked up the part number for the sensor on RealOEM. The diesel uses a similar looking sensor to the gasoline 3.0 X5, same price, but one digit different in the part number, same price. Perhaps the sensor is calibrated differently. It does look like it is there.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue