replaced thermostat not over heating but still goes up

[wantarace95GSX]

I just replaced my thermostat and all was fine until about 2 hours into my driving the guage started to go up just a little bit. No where near the red zone but like 2 notches up. I am thinking bad reciever can someone help me?

 

[Defiant]

How old's your radiator cap?

 

[wantarace95GSX]

good point defiant, its the original one

 

[Kevin90GSX]

that or maybe your due for a new radiator.... mine does the same thing.... christmas gift for myself maybe...hmmm