Withought this warranty too you can get oil change service and get the stamp on booklet that will fetch you same resale value whenver u sell. So why pay 3k extra on warrnaty.
check for any leaks, how many KM are done on it,listen to the engine when driving if anything unusual, take the car in highway and go beyond 80 and 100 KMPH and feel the performance also when braking , dose the seller have service history, what was done in major service, is the car accidental, dose he have fines and last get it checked from a mechanic for overall check.
Catalytic converter has to be checked for blockage and also the exhaust do u have black or blue smoke dispersing.
If yes the coolant is getting burnt or it is the engine oil.
Well in Dubai, you can always approach the dealer if you like. lolololol.
Being 2007 it would be difficult to find a used engine in scrap yard in sharjah as it is quite new for scrap guys, but still give it a try and check chevrolet scrap yard in sharjah opposite Abu shagara behind Al falah after Liberty automobile.
However, you can also try to source from the half cut Chevrolet cars that come behind troy university in sharjah.
If its import then please change the thermostat immediately as it might be opening and closing at higher temperature, whereas in GCC cars it works quite early.
If GCC specs car then you should check if all fan is working fine esp AC fan, radiator isnt clogged or leaking, car is serviced well etc.
Never overlook overheating in time or else it will cost you LOT MORE later.