I have a 97 legacy GT and it keeps over-heating the vehicle has 140,000 miles on the 2.5L engine. At first the only time the gauge would start to climb was under high load or when going up hill or at high speeds. Now it has started to do it alot more often. I have topped the coolent up alot recently but I am not able to pin point if it is just boiling over or if it is going out the exaust from a blown head gasket? I was wondering what the average life span of a subaru water pump is or if any one has had similar problems do to head gaskets, rad fans, water pump ect. Also what should I do to test each component.

Thanks

Rad fan is unlikely, as that would tend to hit when moving slowly, like stop and go traffic.
Head gasket is the big bucks possibility. I think it's time to take it to a Subaru-specialist mechanic and have them diagnose it. Overheating can easily damage the engine, so I'd do it sooner rather than later. A water pump could certainly need replacing by 140k, but they usually start leaking for a while before they fail, a little dripping. Another possibility is clogged radiator.
At the least, a mechanic should be able to fairly quickly rule out (or in!) a head gasket problem -- it's worth buying at least an hour of diagnostic time for this.

Have you ever replaced the Thermostat or Water Pump? I see you have 2.5 liter, hopefully it won't be the head gasket which can be confirmed via compression test or cylinder leak down test. As for the water pump, it will leak when it goes bad or whine if the bearing goes. The Thermostat will either stick open or closed, when it sticks closed, your car will overheat. Start your car in the morning and let it idle. The thermostat runs to the bottom hose, but if the car is running hot and one of the two hoses (upper or lower) is still cold, it's likely a thermostat.

-Charles-

I replied in the Legacy forum.