My bad, it's a 92 600 SEL with 110K on it. Well, it cannot be just the guage since the steam was coming out of everywhere. It seems like the thermostat is shut closed because the water in the container is cool. The temp keeps rising once the engine starts and it doesn't take long to go all the way up. The first time happened when I was on the freeway but I managed to drive home slowly wiht frequent stops. Thanks.