T
toeknee
thats exactly what happened to me. New van and it was 4C. When i stopped at lights there was some smoke coming from bottom of van. But it hasn't happened again. I was a bit worried but this comment has put my mind at rest a bit. Will keep an eye on it though.What you describe sounds like the coolant heater that is diesel powered like the auxiliary heater but for the engine. It runs automatically when below 5degres.
very smelly and can smoke the first few times then it improves.