There's no point of hesitation. Fix it once, fix it right
Assuming that your engine block/water pump is badly corroded, it's gonna hold up for now but on the first long journey out of Karachi, it'll leave you stranded in the middle of the road. So it's just a matter of fixing it now on your own terms or the bush mechanic that you'll end up with in a bit of time.
Best case scenario, it'll remove a bit of rust from the system and will run fine from there on...