Thermostat question

I have a 95 grand prix and it seems to be getting a little hot on the highway and hills. It dosnt get hot enough for the warning light to come on but hotter then avg. I was wondering if anyone had any ideas. I think that it is because the thermostat might be bad but im not sure please help.

Those old 3.1L engines the fans didn't come on untill 228*F so the guage really creeps up there.

On hilly roads, the temp creeping up is totally normal. On the highway, unless you're flying along at 80+, it shouldn't heat up. If it's been a while since you replaced the T-stat, it wouldn't hurt to give it a try, as it may not be opening up completely, restricting coolant flow.