poster, @zia1288 has given the best options. 10w40 is the thinnest possible oil available for a mehran, that too by sgo only. use the following guideline with 1 being the most desirable and 3 being the least desirable.
- use SGO PREMUIM 10w40 api sg (NOT SGO ULTIMATE 10w40 api sm). the premuim one is a silver box which will cost around 1210 for 3 litres.
- if u notice any oil reduction from the above mentioned option then shift to zic m 15w40 api sj
- if both the above mentioned lead to oil reduction then use caltex havoline 20w50 api sg.
remember, the less viscous the oil, the better the fuel economy