The weather around here has been in the 30s for a little while now. The other night it was 16 degrees outside and as I was driving home, my check engine light came on. When I scanned it, it said that coolant temp was too low. I noticed that my coolant temp would stay around 160-170 when it's really cold ( 25 or less) and it's usually between 180-190 as long as it's over about 30 degrees outside. Is the change in coolant temp normal for really cold weather? I'm guessing the light came on because the engine computer is not used to seeing outside temps below 20 or 25. What temp does your 2.2 Cobalt run in really cold weather?