I have a 2002 ZD30 patrol and its 5000 km since I did a home service (oil, oil filter, air filter, fuel filter) - which was the first I have done since owning this car. Yesterday I dropped the oil and swapped it out without changing the filter (as I believe the schedule says).
After the previous oil change, the oil was black within 10 minutes of running - which is also my usual experience with older diesels. This time, its hardly changed, pale golden colour after 15k of driving.
Other than the colour, the wagon is driving / sounding great. I did use a Liqui Moly engine oil stop leak 1000 km ago to try and get rid of an annoying mildly weapy timing coler gasket - which didn't work!
Any ideas of why it would be so different this time? I'm super suspicious of things like this. Both changes used Penrite diesel 15.
Cheers.