start with outside radiator inspection ..is air from the grill in front getting to the rad(or is the bra blocking that flow). Is the rad dusty on the front(where the bugs smack into) Give it a hose off(but don't use hi pressure solid stream) as that will bend the fins impeding air flow thru the rad to cool the coolant tubes. Next check the thermostat (get a cooler one or take it out completely). Also check the hose condition on the inside of the hoses(where they fall apart). Take off the water pump and check the impeller inside the water pump and make sure it is tight and rotates like the fan. Also there may be a thermostatic relay switch that flips on the fan when the engine gets too hot. Maybe that is not working. VW Golf has one and has problems with it. The only reason why overheating happens is a leaking head gasket(not torqued down correctly)