I can tell both of you guys are the classic "chalti ka naam gaadi" car owners of Pakistan. The reason you face issues is that most such customers are 100% pennywise pound foolish.
There are very good mechanics out there in Pakistan but they wont be your Rs 500/- labour charges for big work kind of people - sastaa aur tikaoo kaam har waqt nahi chalta bhaijaan. When such proper places repair your car its done to factory specification and that costs money in newer cars.
speaking of your engine heating up etc.
If you regularly open your radiator cap everyday to check coolant then your car is a useless pile of metal in my opinion. This action also invites lots of airlocks in the coolign system which will cook the engine. Get it repaired correctly - there are some very basic tools that can test a cooling system, mechanic squeezing a pipe and saying "gas banaraha hai" is not one of them - remind such mechanic that the 1940s has gone by.
Similarly when replacing your cylinder head gasket the headbolts are to be replaced because they actually stretch out when being tightened, such bolts are used to eliminate the "2nd tightening" after 100 kms that was done in ancient engines. Infact engines now even use TTY bolts for the conrod caps too to eliminate this step. (no new car user wants to pay big labour to open the engine and get these tightened now - it was normal in the 1950s though and people paid.) - If you or the mechanic chooses to reuse TTY bolts for the cylinder head then its 100% guaranteed the job requires redoing.
when the above fails - mechanics start doing stupid stuff like punching out the thermostat, pouring in "speed walay baba ke dumm ka paani" in radiator and finally blaming the manufacturer because you are being a pain to them.
Same with gasketing, if you are using red RTV on engine castings because its half price of the original stuff - it will leak in a few months.
All of the above boils down to a few points - cheaping out service jobs. As with anything you buy, common sense says that you should be keeping it in serviceable condition. e.g. making a wall, you can hire a proper raaj and mistri combo to make it correctly or you can hire a heroinchi off the street, both can make the wall from bricks you provide, however the raaj and mistri can make a proper wall, the heroinchi will pile the bricks up and call it a wall.