Because the current temperature outside is 14° and "feels like" 2°.
Friday, before work, I went to the auto parts store. I took in a car battery I no longer need for the $5 gift card, and I used that gift card to pay for a Felpro thermostat housing gasket. (Of course they didn't have any of the $0.89 gaskets on hand. Argh etc.) I also bought a gallon of premixed coolant, because while I have a drain pan which is specifically for coolant and which I never use for anything else, you cannot avoid losing some of the stuff you drain from the cooling system.
But it's just too f-ing cold outside for car work. If I had enough room in the garage that I could get the Jeep in and close the door--but I don't, and no amount of wishing will change that.
It's probably better to plan on doing the work on Tuesday, instead, when the temperature is supposed to be as warm as freezing, and (as a bonus) I'll have another day--Wednesday--on which I can finish whatever I haven't accomplished, if need be.
...and that also lets me take a much-needed nap. I got perhaps five hours of sleep before getting up for church this morning, so I need it.
* * *
Speaking of which--