Used Petron 5w30 all terrain oil sample from 3.0TD trooper (mileage of 38k kms) after 5000kms use, tested last 11 march 2003.
Test results:
KV at 40C 63.12
KV at 100C 10.47
Visc index 155
TBN, mg 14.1
Pentane insolubles,% 0.09

1) Viscosity decreased slightly from 74.3 at 40C and 12.06 at 100C when new, still within a 5w30/ 10w30 spec. Visc index still high as expected from a full synth oil.
2) TBN- from 16 new- only decreased to 14.1 which means high retention of detergent/dispersant additives so better protection from engine wear and bearing corrosion. Normal oils may see TBN halved after 5k kms.
3) Pentane insolubles measure dirt, dust, metals in oil that wasn't trapped by oil filter. Indicates quality/ life of oil and air filters, engine wear. A safe/ max limit of 2.0% so result of 0.09% is a long way off.

Based on these results, IMO, the oil is good for another 5000 kms use but may opt to change oil after 7k km. Looks like a good oil for the 3.0TD trooper! :D