I totally agree k 5w30 is the recommended oil. But the poster has been using 20w50 , so I would suggest k he shifts gradually and easily. Sudden shifting from 20w50 (very thick) to 5w30 (very thin) can be risky. Just pour havoline formula 10w30 this time and use it till 4000 kms and observe the oil level in the morning in dead cold engine for level reduction. If no oil reduction till 4000 kms then shift to shell helix hx7 5w30 after that. If u witness any oil reduction, then tell us. we will recommend another solution