no problems. I shifted my 90k driven corolla directly from 20w50 to 5w30 when I came out of Lubricants zamana e jaheliat. Thanks to @Xulfiqar for encouraging me to do the dare otherwise mechanics and even the 3s dealership foreman was against this switch. They were of the view not to switch otherwise engine will start consuming oil and if at all I need to switch then they proposed to do it gradually and check like 20w50 to 10w40 then 10w30 and then 5w30 but I switched directly and now ma sha Allah my car is driven 150k without any issues. After the switch it felt like I have unhooked an invisible trailer attached to the back of my car. The car had been with me since brand new and was always poured with 20w50 petron by the toyota dealership. First I switched to Total 5w30 and later on discovered company operated outlets of caltex and switched to Havoline 5w30 and now sticking to it because I found it better than the Total oil. Earlier I was changing the fully synthetic oil as well on 5k but again sir @Xulfiqar came as a savior telling me that I am wasting money by doing so hence now first I extended the Oil change interval to 8k and then stretched it to 10k with oem filter from dealership. This time I am planning to stretch it to 12k kms given the jacked up prices of the lubricants to have full benefit of the synthetic oil in sha Allah. I have changed oil filter though at 6.5k kilometers.
Hope that helps. Happy motoring!
