Amsoil is actually the only fully tested oil that is rated for the highest mileage of any oil available in Pakistan. It's a true synthetic. It costs a little more than the so called Mobil 1 0w40 but lasts and performs ages more than the Mobil 1.
Something interesting on another note that I experienced:
I have a high mileage engine in my possession, I was loosing a quart of oil every 3k km's. It was about time to step up to a high viscosity variant. I went for Taglon. My engine has a lot of sludge deposits, because of extensive usage in village environment where it did 50k km's of running on I am sure fake oils. The guy who filled the oil overfilled it a bit. Next day I go to get that oil removed and guess what taglon has turned considerably black.
Morale of the story even an ordinary flush does not do anything. Because I have done it before and oil comes out quite golden. Why did the taglon turn black in one day? Simply because I had a high speed run on the ringroad in this one day and this is what would constitute as a proper flush had I done it for a engine that is sludgy like mine.
My next oil change will hopefully look like this.
- Get cheapest mineral oil that confirms to viscosity and API classification of my car. New filter.
- Give the car one day of hard driving.
- Replace the old oil with proper synthetic and new oil filter.
For reference my car's mileage is in 250k+ KM category. But with what I have seen with my own eyes, it's clear a normal flush does not work as well as we imagine it would. Secondly the dip stick if it's stainless steel like mine was still showing golden oil even the next day, when the oil came out it was saying an altogether different story. There's is a high probability the filter isn't doing it's work. To test my hypothesis I intend to import filters from the US to ensure that section is covered.
So for people thinking 8K km is a good interval for oil change, I think it's unwise. No local filter or so called genuine filter or oil is made to withstand that form of abuse in our stop and go traffic.