i need to change engine oil for mehran 2013 model. its
driven 46000 km. previously i used Zic X7 10w-40. should i go for 10w-40
again or switch it to Zic Hiflo 20w-50 or Zic A+ 5w-20. im also
confused what is exactly the difference between 5w-20, 10w-40 and
20w-50. which will be the best oil according to car engine and current
pakistan weather.