limit airflow thru rad ??    (1/2 cardboard)    Anybody else?  

I've tried the cardboard in front of the rad.  But it was on an old car, and only to counteract a failed thermostat. And I don't think that it will help much in the severe cold of -38.

I would replace the thermostat, either with a new OEM, or with a Stant equivalent (the one with a long spring).  Someone on this board has a photo of the best thermostat to buy.

But I don't envy you working under the car in such cold weather!

EDIT: Just noticed that you have 2018. Take it back to the dealer...

Edited February 1, 20197 yr by forester2002s