As the car was reducing half liter engine oil after every 3000km.
So in January 2021 finally decided to took apart the head and i was in favour of only rings and valves seal replacement.
When the engine was taken out and opened the rings were shot allowing too much oil to pistons, rest the pistons, cylinder walls and other things were in pretty good nick but the mechanic insisted to go for complete overhauling on his risk to avoid any issues in future.
So i let him do his thing.
Things changed:
Piston 0.50
Rings
Valves
Valves seals
Crank pieces
Main oil bearing
Gasket
Oils etc
Took 3-4 days.
Total cost:
Engine parts Rs 20000
Khairad took Rs 8000
Mechanic labour Rs7000
When the engine was started afterwards its was 100% smooth, silent and just as before.
But unfortunately i went with my family to my nani house for the next day leaving the car to mechanic and electrician to windup the remaining work.
When i got back, the car engine was running like a diesel car/ tractor 
.
When i inquired about this whole thing i got to know that someone from either mechanic or electrician side had been accelerating the car on idle. But nobody knew who did it.
Khair told the mechanic to again took apart the engine and check what needs to be done.
Found the crank pieces was worn out because of that racing up the vehicle by person unknown.
Again bought those crank pieces for Rs3000 and fit it back.
Changed gasket and engine oil. Fired up the engine and it came out just like a factory engine, smooth and silent. 
Didn't pay anything for 2nd time work.
Kept it running for 3-4 hours and spend all day in workshops to supervise the work.
Brought it back home and drove it 800km break-in period in a month.
Changed engine oil after 800km. Used shell 10w-40.
Milage at time of overhauling was 12000km.
Milage in july 2021 was 18000km.
6000km after engine overhauling. 2 oil changes.
Been to Abbottabad, Islamabad, Peshawar, malamjabb, kalam, mardan etc
Engine is very smooth, noiseless and performance has increased.
No issues so far.
Fuel economy 7-8 km/l in mingora city with full time Ac.
15-16 km/l on highway with full time Ac.
This is 350km in half tank on long journey. The car easily gave me 600+ km on long when reserve start blinking and take around 38 liters to fill up.
All these are Ac figures.
Without Ac 1-2km/l improvement.
