The problem might be coming from a faulty coolant temperature sensor. If you can do it by your self you can test if the gauge is working by locating the coolant temperature sensor. One wire lang yon alam ko. Malapit sa may cyl. head cguro yan. If you can locate it and are pretty sure that it is it, tanggalin mo sa connector tapos yung wire na papunta sa luob ng tsikot i-ground mo. Takbo ka sa loob ng oto para makita kung umangat yung gauge. Pag-umangat yon ibig sabihin faulty na ang sensor at kailangan na palitan. Estimate ko mga P 600.00 siguro ang price ng bagong sensor.
***dont try this unless you're pretty confident and have a background on AUTOMOTIVES. Better yet, have it done by your favorite mechanic.