I have a 96 subaru legacy wagon with around 150000 miles on it. It has intermittent overheating problems (every couple of weeks). The radiator and thermostat were replaced about 2 months ago, I understand one cause of the overheating besides problems with the head gasket is not properly bleeding/burping air from the system when coolant is refilled. Would air have worked its way out after 2 months or could this still be a problem? How do I tell if this is the problem and how do I fix it if it is?
BLEEDING COOLING SYSTEM
Always bleed air from cooling system after replacing coolant. Set heater for maximum heat. Remove radiator cap. Loosen drain plug and remove drain bolt (if equipped) from engine block. Drain coolant reservoir. Fill coolant reservoir to MAX mark with 50/50 water-coolant mixture. Loosen bleed bolt and fill radiator up to base of filler neck. Close bleed bolt when coolant flows out without bubbles. Tighten bleed bolt. With radiator cap removed, start and operate engine to normal operating temperature. Add coolant if necessary and check for leaks.