its been a hit and miss with me, the oil i got one was form clatex pump don't know if it was company operated and other one was form a reputed shop, the shop one was more expensive and performed better both had same packaging, i used dell gold in my yanmaar 25kva generator then used dell gold ultra, then liqui moly 20W-50 formula super, now using Mobil 1 15W-40 delvac with liqui moly ceramic treatment in generator, liqui moly was much better than delo gold, just changed to mobil 1 couple of days ago so can't say much for now, and yes pakistani diesel is bad and higher end oils don't really go well with it, its a different story with petrol in my situation though, used mobil 1 5W-50 fully synthetic in a 136k driver corolla gli driven on toyota 20W-50 since day one, many advised that seals would leak etc, but mobil 1 was SN and SN oils have better seal compatibility, and its running without a hitch, no reduction in oil what so ever or any leakage and night and day difference in response and fuel economy