Okay, here's what happens; Usually, my temp gauge doesn't budge, it just sits all the way down. Just recently, since it turned cold here, it has started to go way up, almost to the redline, during the first fifteen minutes of driving or so. It will start to rise steadily after a couple of minutes of driving, peak near the redline, then steadily go all the way back down. This is after letting the car run for about five minutes before starting to drive and also without giving it too much gas, making the engine work hard (i don't ever rev it above 3K for example) and with the heater on and blowing hot. The only other times that the gauge has done anything is if i sit in traffic for long, then it will start to rise, steadily again, and steadily go back down once i'm moving again. When it does this, i run the heater to try and help cool things off, that has some (not much) effect. I hope i explained this clearly and thanks in advance for any help. Also, the temp gauge has been like this since i got the car (3 years roundabouts), my brother had the car before me and says that he recalls it working fine, showing at 9 o'clock and such).

1988 240DL 157K(?)