94 ls integra coolant gauge prob. ?

I just bought a 94 ls integra and the owner had just put in a new radiator and ever sence he said that the coolant guage doesnt read right. Most of the time it will just stay at the bottom but every once and a while it will go up a little. The heat in the car is never that hot it is warm but it never gets as warm as you would think it should. What are your thoughts could it be a thermostat prob?

Yes it is the thermostat, the spring has gone bad in it and so stays open all the time. Replace it and that should take care of your problem.