I have a 98 legacy outback and just recently the engine overheated but instead of it just overheating my headlights would dim in 'pulses'. Once it overheated, I let it sit for a while and when I went to drive it again the temp gauge stayed in the proper spot for about 2 miles before jumping up again. I have heard of alot of head gasket problems, but that wouldn't cause the lights to dim, would it? The belts look tight and without cracks. It also seems to be burning through spark plugs pretty regularly as well. It will be fine for about 1000 miles or so, then start to hesitate when given gas from a stop. My gas mileage has started to get terrible too, 3 tanks of gas for 650 miles, all highway. Would a good start be timing belt, water pump, thermostat?ThanksThe engine has not overheated to the point of not working anymore. Luckily it was caught before it got too out of control.