The temp gauge isnt getting up to its norm and the heat isnt as hot. Does this sound like a bad thermostat? I didnt want to give an opinion because I wasnt really sure.
You didn't post your location or what the temp is like outside. During the winter, I have to block off a large portion of the radiator if I ever want the car to heat up and stay at operating temp. Your only problem may be that your cooling system is being efficient. Perhaps too efficient for the declining ambient temps.
I put in a 180* t-stat a few weeks ago, and the car would never get into the normal brackets. I swapped it back and now it runs between the "N" and the "O". You might need to put a higher temp t-stat in.
Thanks for your replies guys. We live in Mass and its fairly cold now and he said he just started noticing that it wasnt as high on the temp gauge as it usually is. He says it never passes the bottom line of the NORMAL markings. And he said his heat is still decent and hes not sure if he only thinks it may not be as warm because of the fact that he noticed the temp gauge issue. Which might not even be an issue... I think he might just be stressing it too much but it never hurts to pay attention I guess.
If it's doing something this winter that is DIFFERENT than previous winters with the same parts, then yes, it's possible your t'stat may be not be closing all the way when it's trying to modulate engine temp. The common symptoms for that are lower engine temps, and heaters that take longer to start working, and don't produce as much warm air. OH, and gas mileage may suffer along with automatic tranny's that tend to hold the lower gears longer before they shift -- just like when the car is running cold. Because it's running cold longer.