It has been very cold where I live for at least a month and a half now, and this being the first winter with the TCH, I was very curious how it would behave with extreme cold. When our first cold really came, I noticed that my SG would register engine temperature of about 50C to 65C (122F to 149F) for city trips. (half hour or less). I got worried, since we get cold weather for four to five months. I also noticed that without the SG, there is no way of knowing what the actual engine temperature is sitting around, since the engine temperature gauge in the dash is more of an idiot light with a needle since it shows the same level if the engine is at 50C or 90C (122F or 194F). Not very useful these electronic gauges... anyways the engine was running too cold for my taste and as a side note, my front grilles are completely blocked with the fabulous pipe insulation (slick that stuff). If I was to press the eco switch on, wow, the EV mode would come on even more when stopping at lights, and the engine would stay cold between 50C to 60C, and the occupants would never get warm.
Soooo this is when I thought that I would try to put the heat to HI and leave it off auto. Well, without understanding how this can be, the engine warms up to 80C and 90C (176C to 194C) and heat is very generous in the cabin. Of course, my consumption is high, but I am happy and warm and the engine will thank me latter....
Cheers

 

it is normal for TCH ICE to run nonstop when cabin heat demand is high and that in turn keeps engine warmer. I think TCH has normal thermostat and no other way of regulating engine temperature except for the usual electric fans kicking in when temperature is high, so forcing engine to run at all times by demanding max heat makes all the difference.

 

With the temp up to high your running on mostly electric heat. It comes from the deep cycle 12 volt battery in the trunk. As long as your driving this should be a good way to keep warm. I put mine on high temp as soon as I start up on any cold day. After my car reaches warm enough I turn the temp back into the 70's. If it's cold enough where you live, you may have to leave yours on high most of the time.