it could either be a clogged radiator or a near-replacement na water pump.

a faulty water pump will show leak signs sa water pump (dried watemarks or wet yung water pump).

pag clogged ang radiator not all the water could be "cooled" by the fan when it is in idling kasi blocked na ito. A clean up is in order, he'll probably spend P300-500 for that repair.