Aoa i have Toyota fielder automatic ODO 250k km
Mechanic suggested my father to use 20w50 as car engine was old and my father did started to use it
Now when i started to drive car i learnt that 20w50 is used for almost dead engines with problems
Now I'm thinking from changing to zic 10w40 synthetic
My car so far doesn't have any engines problem as much as i know
According to my father he has only used 20w50 only 4 to 5 times changing it timely and was using zic (grade not known) before
Should i stick to 20w50 or try to change it zic 10w40 and if should change what should be the intervals of next oil change and any other things which i should know
