Re overheating: Tumataas ba temp pag stop and go traffic? Meaning pag umaandar na eh bumababa ang temp at tumataas lang pag naka stop? If this is the case, might be the thermostat. Pag nauubos parati water reservoir mo, may pressure leak ka somewhere kaya di bumabalik water from radiator to the reservoir: 1. cylinder gasket 2.radiator cap 3. sa water reservoir mismo. 4. hoses 5. others ( di ko na alam).
Hope this helps