i found this interesting diagram @ a site..
according to this if we use an older API rated oil in our car the engine/ other components will be seriously damaged.
API ratings are backwards compatible meaning you can use an API SN oil in 1992 corolla/civic however according to the book you cant use API SG oil in 2006 Corolla/Liana/ Civic..
Can any learned members please elaborate this point? dont know whether most members know abt this??
harsh weather climatic conditions ie summers are asking for a thicker oil specially in summers like 20w50 so why are most top brands 20w50 oils available in Pakistan rated as API SG or SJ???
seems confusing to me cause when i use the red Caltex Havoline 20w50 ie API SG in my baleno/ corolla the engine is much smoother..:-!
also other top brands like Castrol GTX (20w50) is also API SG:S
what bad effect can an obsolete oil grading like API SG have on engine??
the charts is here..