This engine is a 4.2 litre, indirect injected low boost (approx 7 psi) turbo diesel.
It is worked pretty hard, towing competition dressage horses regularly. Not bad results for a 20,000km OCI using a non-approved lubricant. The factory recommended OCI is 5,000km, (filters @ 10,000km) and only CF or CF-4 oils are approved. According to Nissan, oils such as D1 that also meet CG-4 up to CI-4+ are not capable of providing valve train protection. Nissan advocate oils using in excess of 3000ppm Calcium.
Mostly the manufacturers know what's best, mostly.
From the factory, this engine utilises two oil filters, a full flow and a combination full flow/by-pass filter. For this OCI, a Donaldson P169071 Synteq media filter was used for the full flow. The OE filter doesn't use a by-pass valve, as it's block mounted. An OE Nissan combo filter (this one made in Thailand) was paired with the Donaldson.
A GUD/Ryco air filter element is used in the stock housing.
Redline's RL2 and 85 Plus (when RL2 isn't available) fuel additives are used at a maintenance dosage for pump/injector lubrication and to help reduce soot levels in this indirect injected engine, although I'm sure that our 50ppm sulphur diesel also helps in this regard. The diesel used is either BP, Shell or Caltex/Woolworths. (It's SWMBO's vehicle and she insists on using her shopper dockets.
Sump capacity is 10.5 litres. There is a block mounted OE oil heat exchanger, and their isn't any intercooler. The OE turbo is a water cooled Mitsubishi TD05.
On a cost/benefit analysis, we are already ahead at this OCI, and with these numbers, a much longer OCI is easily achieved.
I'm guessing the previous analysis reflects the Delvac 1 'mopping up' after a thorough Auto-RX clean and rinse.