I recently got an 85 300sd with an engine that only has 92000 on it. The car drove great till I heated it up on a 30 min trip home from work during the hot part of day. I was just about home when I turned on the A/C, ahh it was nice and cold, but at a stop light the engine started to make some strange vibration and a few minutes later coolant vapor burst into the cockpit (not very nice while you are driving). I got the windows down and pulled over and the vapor slowed down, but the engine temp started to get hot. I made it home and found the passenger side floor wet and the coolant was empty. I can't find where it is coming from. Any ideas?