I have suzuki mehran 2006 driven 60k kms. I was using ZIC A but the car started to decrease oil and i changed after 1.5k kms and oil that came out was black and when i touched oil on dipstick it was very thin like it had lost all its viscosity. Then i shifted to LM 10W-40 heard good views about it after changing oil next morning i check dipstick it was in mid of 2 dots. Previously oil drain nut was bad and car was loosing oil although no spots in garage but oil guy said it gets out mostly while driving. Is this normal? mechanics here are rip off i went to my mechanic and he said the car has weak rings and valve seals and requires head overhaul. My car is not giving any smoke not blue and not white. Another guy with mechanic suggested me that use 20W-50 its good for mehran i said that it should be used after 100k kms but he says he is using it in his new mehran from day one. From where can the oil leak? engine oil cap and drain nut is also replaced now but the level is in mid on dipstick mechanic says the dipstick should have some oil it should not be dry and you can run like you have it in mid and i said that car has to bear more wear and tear. @Xulfiqar please help and give your valuable suggestions.