awwwwwwwwww overheat......possibly water jacket......
1) check if u have coolant overflowing on the floor after some drives......
2) check if after after engine cooled got water disappearing
3) check for champagne bubbling when cold starting or heavy burping
4) check if all your fan belts are in tact... if ur water pump is f**ked, u'll overheat..
don't worry.. it's not apex seal.. but it's almost same shit... rebuild...
I reckon go and do a coolant flush (can check the thermostat as well). After that, replace the cap too just in case the spring fck up and cause no/too less pressure in the system. Water pump is not too difficult to to be removed so may as well open it up and see if got excessive wear out on body structure or fins that can cause internal leak (less volume to be pump to the radiator). 2 stupidest things to do before you heading to anything else are to check if your fan still working and the the radiator fins are ok.
Id go with what Alc and CSL have suggested, ie do all the test to confirm the actual cause of the problem before investing into repairs/replacement of what may not be necessary. It may turn out to be a very simple and cheap repair after all
Just acquired an Airtrek Turbo over the last few days, and has been quite an experience. There have been a few mods done to it by previous owner, and has been great.