The originator of this thread asked for a canadian opinion. So here goes. Why do you think we all go to florida for the winter season? It's not that we have money, it is the only way we know how to get our diesels to start. It can be -20 outside my house but my diesel catches on the first glo cycle here in Florida. Really though the cold seems to be a good way of evaluating the general condition of diesel engines easily. A really good high compression engine seems to cold start to a much lower temperature than an average example. Brian is completely right as there is no standard to really apply.. In your case you might consider wiring the car with a remote starter and on days when the temperature is questionable have your wife start car and let it run during lunch breaks.Only uses a pint of fuel at most. Have seen the simple kits with extended range getting pretty cheap lately. We canadians really have no solutions other than block heaters that tend to save a certain amount of wear to engine as well as extend glow plug, starter and other components lifespan. If I had to depend on one of my old 616-617 engines in winter think I would purchase a small 1000-1500 watt generator and set on ground behind trunk for the few occasions that the engine had cooled down too much away from home to self start. With block heater cord wired to trunk area it would only mean setting generator on ground plugging in block heater and really swearing if the gas generator did not start. A few other no start stratagys. Be creative, tell the car you will part it out for refusing to start. Mention it will not have a hope of seeing 500,000 miles but be careful as car may recognise this as an idle threat. My wife on occasion gets me started with threats so why not the car? Buy a cheap reliable gas beater for the really questionable part of the year. Not really wise to get our wives upset as they can self start on occasion without any assistance at all it seems at any temperature. In kind of an inverted logic you do not want them to start even when it's -20.