Coldest ever for me was my 73 340 Duster back in 1980. Temp here dropped to -3 F and I drove it to work thru the snow like any other day. Around here cold or snow is a severe event.

To you guys up north what we called the "blizzard of 80" would have been a flurry and the temp would have been a thaw.

Bismarck ND set a record low for the date at -40 last night.

Its been -30 or colder here the last few days and I havent had any problems with my car. It starts up and moans for a little bit but runs fine. Its the only car I have that doesnt have a heater to plug in. Ill probably change to some different kind of oil on the weekend. The worst problem is waiting for the frost to get off the windshield.

Friday morning was -11 here in cleveland. My Trailblazer SS started like it was summertime.
I have 5/30 mobil 1 in it. Mike

I'm running 20w50 in both my '95 Dakota and my '81 D-250. The Dakota pops right off with no problems, its nearing 200k however and its a loose motor. The motor in the D-250 only has 28k on it so I'm considering switching back to 10w40.

I've had to drop oil in it in the mid 20s and yeah that 20w50 was pretty danged thick. Came out like goo out of the cold bottle. It also takes some time when its cold out to get the lifters pumped up.

I fired it off last week in mid-teens weather and it did okay once the oil got to pumping (took a few secs though). It did crank slowly though.

I've had several starts over the last week at -17 and -18 with a Hemi Durango running 5W-30 synthetic oil. It started right up and no OP problems. If I had to do it on a regular basis I'd run a block heater to make it easier on the engine.