Which oil for a 12J Diesel

I've just fitted a 12J diesel in what seems to be VGC.
What oil should I be using to minimise engine wear and make this lump last as long as possible ?
I'm not the slightest bit interested in reducing internal friction and getting better fuel mileage, or reducing mechanical noise.
I just want stop my engine internals wearing away.

15w40.

Henry_b said:

15w40.

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Can using a less viscous (thinner) oil cause lower rates of engine wear ?
Apparently it can, but I don't quite understand how.
Except maybe in extreme cold conditions.
Looks like I need to deepen my understanding of how multigrade oils work

I put this in my 200di

When I stripped engine it was spotless and unworn inside with no build up of sludge anywhere and noil galleries clear , I wanted to keep it that way and dont mind paying a bit extra

Engine good 15/40
Engine worn 20/50

lynall said:

Engine good 15/40
Engine worn 20/50

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In the case of the "boat anchor" that I've recently removed, 20/50 with about two litres of used EP90 added to it.
Desperate times call for desperate measures