I have slept in a 240d with the engine at idle all night. I drove as long as conditions would allow. There was still maybe fifty miles to a motel.

I was not certain that in those conditions the engine at idle would create enough heat but there was no choice but to see. Suprising to me it did well in that regard. There was no more snow falling and basically everything was ice at the elevation I had to stop at. So no chance of trapped exhaust fumes if the snow accumulated especially with the wind that was blowing.

I was aware that some components of diesel exhaust can make you feel ill. This after driving hours after ripping part of the exhaust off on a road under construction with a jetta diesel. I should have kept the heater fan on to give the cabin more positive pressure. The unwell feeling only occurred or intensified after I stopped . Did not last that long. The north shore of lake superior is a long haul especially when the whole surface has been removed for processing first and later re application.