I just ran across an interesting website from New Zealand. Obviously the info applies to oil sold in NZ, and can't necessarily be applied to USA or other places, and the info is specifically about Toyota diesels, not Isuzu gas engines. That being said, this may be part of the trouble with oil consumption and/or leaks and/or other problems in later model Isuzu engines.

http://www.a1.nl/phomepag/markerink/80bigend_oil-analysis-scam.htm


2x '88 2.6L Troopers (one for parts)
'86 2.3L Trooper
'99 Acura SLX