I wouldn't use anything less than a 15w-40 oil for diesel engines, I have been using rotella T for many years and am happy, walmart sell for a good price.
15w-40 to 20w-50 are recommended by LR for the 200/300Tdi's
But there are other good brands out there Delvac and Rimula R4X
Diesel engines need to have oils with higher Z's and detergents which petrol engine oils lack now days.
As for the Mobil 1 save it for the car
Edward Teach is the Blackbeard, and is a member of the Birmabright Brotherhood.
Still looking for that place where I can carry a paddle and get asked what's that.
FC101 GS FFR
57 LR 88" SXF 858
95 D1 Tdi
05 D3 HSE
97 XK8 BRG FHC For Sale