Hello guys
I am using vitz 2014 from last 4 years. My car mileage was 45000 from that time I am using shell Hx7 5w-30 as engine oil. Now my car mileage is 87000km. should I change the viscosity of engine oil if yes which one is suggested?
Note: using 5w-30 till now I have not faced any problem but car efficiency is dropped from 18km/L to 15.3 km/L.
Thank u