thermostat gauge

my friend's 95 civic's heat gauge on the panel shoots up all the way until it reaches steady speeds (55-60 mph). weve looked into the thermostat and all, and got it to stop doing this for a day but it came right back the day after. if theres nothing really wrong with this, thats what im looking for but id like to know if theres anything that can be done to stop it. thanks

so youve replaced the thermostat.. or just checked it? u may also want to flush the radiator cuz it may be getting clogged.

If the car runs cool when the engine is turning faster and coolant circulates quicker as it does at freeway speeds the problem is not water flow. The problem is air flow. Freeway speeds create air flow thru the radiator. Electric fans create air flow at slower speeds when more air flow is needed.

Touché....check your fan relay as well....