I have read many BMW forums and threads to learn that BMW NA does not approve of such. I live on "Devil's Island" (Roundel, Nov 2013), 25 square miles, where a typical winter day's drive might be ten miles, hardly enough to warm an engine. Indeed, in ten winters my previous diesel VW TDI did not ever reach normal operating temperature of 190°F indicated. Is there any positive experience with a block heater installed on a diesel BMW? I am not so concerned with starting ability as with overall longevity, economy and comfort. My VW started reliably at -25°F, once at -35°F. My 30 y.o. diesel tractor without glow plugs starts at 0°F.