owing a 1980 300d , generally from oct 15th until april 1 , i had pluging the circulating HEATER AT NIGHT ....... THE 1987 300TD HAS BEEN PLUGGED THE LAST 2 NIGHTS..... FIRST TIME THIS WINTER....... TEMP AS I WRITE IS -32 WITH WINDCHILL IS - 42c WHICH IS APPROX -40 F.... THE 1987 300D IS THE BEST STARTING DIESEL I HAVE OWNED, I HAVE HAD FORD,CHEVY, ISUZU, VOLKSWAGEN, PERKINS(COMBINE) VOLVO( TRACTOR)(DIESELS...............MANY PEOPLE WILL NOT BY DIESELS BECAUSE OF OUR WINTER WEATHER IN CANADA........ AC....