Hello again!

If I could get anyone's opinion, expert or otherwise, I'd appreciate it.

93 wagon, 192,xxx miles.

I think I need a new thermostat. I've got a little bit of heat coming out now-- on the highway, say-- but very little in city driving. I'd changed out the heater control valve, the plastic one, this summer when the trickle of heat was too much, but realized this fall I had no heat. I thought my heater core was clogged or stuck with a bubble of air, but I have warm/hot tubes on either side of the valve. I just checked last night in the rain after a miserable drive in the cold. So... I think the valve itself is working okay.

There is plenty of coolant in the expansion tank, so I think I'm okay there, too. I don't seem to be losing it (coolant, at least), either.

By my research here it seems like the thermostat might be the way to go.

My questions:

Is the thermostat the right diagnosis? If so, I see there are several kinds offered. I live in New England and appreciate my heat. Does the temperature rating of the thermostat matter in what I get in the cabin?

Can I buy one of these at Autozone or the like tomorrow or do I have to order it and deal with cold driving until it comes?

Am I crazy? Is it just crazy coincidence that the thermostat would fail around the same time I did that job? I've only had this car a year and a half. To be honest, the heat was never like it was in my 89 or 90.

The temperature gauge is no help. It's all over the place like all my other 240s.

Thanks for reading and thanks for any input-- on Shabbat no less.

cheers,
cg