Just over the past year I have noticed that my car's temperature gauge
behaves differently from what I have seen in the past few years. It has
always quickly warmed up to the Normal position and stayed there pretty
much rock solid regardless of the outside conditions. Now, if the car is
moving it barely gets above 70, and putting the heater on also keeps it
low. If I sit in traffic for ages it does go to the vertical (normal)
position so the indicator itself is OK; but it will come down as I drive
along. Also the heater itself used to be great, you'd be absolutely
roasting in a few minutes, now it gets warm but not hot.