have mira es 2012 model, mileage so far is 94000 km. Its was on 0w20 throughout but recently a mechanic insisted for 20w50 instead of 5w30 or 0w20. He said on this mileage synthetic oil is not recommended. But after 20w40 oil my car is giving jerks and sometimes uthane mn bhi masla araha. Keep in mind that 1 month ago my engine oil became thick with sludge. So they did not clean the engine and poured the 20w50 for the first time. Kindly guide what should i do. Its been 800 km since the 20w50. Should i change the oil so dirt can get cleaned? Whats you suggestion?
