I generally run 5W40 full synth in the 1KD and thats what went in the other day following cambelt and water pump change, it also goes in the Forester.
When i first got the motor the engine oil would darken more rapidly than i liked following oil change despite it good SH, so i bought some 10w40 Diesel specific semi synth in the (probably mistaken) belief that oil specifically for Diesels ought to have superior detergent content, got through a 20 litre pack in a few short changes following which the oil stays cleanish now for nearly 1000 miles, same as my Hilux 3.0 litre did when that was new.
Its not easy to find Diesel specific 5W40 except for VW spec probably meant for their PD engines, which i'm unsure about.
I usually get Fuchs, but have used all sorts of makes over the years when there's a 20 litre bargain, interestingly the engine seemed noisy/rattly when i used Shell Helix so won't use that again, and years ago my 70 series sounded like the big ends were about to drop out when i used Comma.
I don't use 5W30 either, gnats piss.