Yar abid bhai 20w is for winter.
Ya standard temperature cranking.
Usko kyun cherhtay hain log.
Agar issue hai bhi to 40 ya 50 increase karen but don't touch 5w 10w and don't make it 20w.
Liquimoly ka 10w60 fully synthetic dal le banda jisko koi issue horaha hai.
Baki if engine starts eating 10w40, to its better to swap it or rings replace karli jaen. Because feeding thicker oil kills the crank bearings and cams