98 Subaru Thermostat Location 98 Subaru Overheating W/ Lights Dimming.....?

98 Subaru Overheating w/ lights dimming.....? - 98 subaru thermostat location

I have a 98 Legacy Outback, and more recently, the engine overheated, but only an overheating of the lights in the so-called pulse low. "But as soon overheats, allow to stand for a moment and then press the temperature display space for about 2 miles before the jump stopped again. I heard a lot of problems connected to the head, but it was not the lights, right? Tight belts and look for any cracks.
It also seems to be that the spark plugs burned fairly regularly. It was good for about 1000 miles or more, then begin to doubt if a particular gas stop. My gas consumption has started to be too terrible, 3 gas tanks of 650 miles, all highway.
This belt would be a good start timing, water pump, thermostat?
Thanks