Most likely a clogged radiator. I had the same problem last year. Nag pa "Top overhaul" pa ko. Nag overheat pa din :umm:. nung pina overhaul ko radiator ko. Di na nag overheat. Up to now di na ko nag ka problem sa overheating. Have your radiator overhauled first before anything else. most of the time yun ang cause nung overheating