oil standards, read if you care about your engine

[dfreeman616]

poking around on NAXJA, i found a thread on the best oil for a 'high mileage' :teehee: cherokee with 120,000 miles, which then had a link to this thread about changes in the past couple years in oil grades. basically, if i read it all correct (and i'm not done quite yet), EPA and API (American Petroleum Institute) standards changed in 2004 to prolong the life of catalytic converters in modern cars, thereby reducing emissions. they did this by reducing or eliminating the amount of ZDDP, an additive with zinc and phosphate which creates a sacrificial layer that reduces wear in engines. this isn't an issue for newer cars with overhead cams and roller tappets, but has been known to cause premature failure in flat-tappet engines (such as our engines). :eek: :headpop:

 

so basically, avoid SM and SJ-4 classification in oil.

[pingpong]

So if 120k on the odometer is high mileage.... I better start using that fancy dancy high mileage oil then :nuts:

[BLHTAZ]

AMSOIL has been my ONLY choice for all of my vehicles for nearly 10 years now. It is the only choice for me :D . With 100% synthetic, I don't have to worry about these things.