Yes 131,000 miles sounds better, though I have had those engines in Iveco Daily's at 230,000 miles running sweet with no oil issues and some quote half a million miles.
It's not the camshaft oil seal is it?
The reason I mentioned the life it has led, is frequent oil and filter changes with good quality parts and regular cambelt kits usually keep them running happy.
It is a solid heavy slow revving commercial style engine so needs to be warmed up well before any hard use and is what I have always done on the ones I had in the past.
I put one of those in a boat in place of a 3.75 litre V6 150 hp petrol engine and it weighed more than the original V6 Buick engine (known as a Volvo Penta 150) so a lot of metal to warm up. It was the pre JTD non ECU from 1997 from a Ducato Maxi van, after tweaking the pump and turbo it managed 26 knots compared with the 30 knots of the original V6 but at 4 gallons of diesel compared with 10 gallons of 5 star petrol of the original.

I used to run mine on Iveco 15/40 oil and never gave it hard use until temp gauge got up to the middle 90 degrees Centigrade approx.
An experienced mechanic can soon see by removing the oil filler cap and holding their hand over it if it is "blow by" from engine wear or not.