Sounds logical. Outside temp of -5. = Subtract for 65 mph and windchill. I had heat, but noticeably cooler to the bare = hand. Never did warm up the van in 50 miles. I thought maybe this was par for = such a cold night.

I'll order a thermostat.

FWIW, upon restart the eng sounded and felt 100% = normal-just heated quickly. This leads me to believe valves and other biggies = were spared and maybe it is as you suggest.

Should the coolant mix be "thicker" than = 50/50 in extreme cold?

Thanks for the response,

I'm trying to clear garage space to bring her in. = It's too darn cold to do anything outside. See also next post. J

Had a similar situation with our Jetta last = winter. It was a freeze up. I had changed coolant earlier in the year, = apparently got the mix wrong and the coolant froze in one of the = hoses plugging the flow. Big time overheat when the temp was 5 deg outside. Took over an hour for the plug to thaw, then back to normal. Another possibility is a stuck thermostat. The = spring in the thermostat will theoretically pull it closed tighter and tighter = as the temperature drops. Maybe tight enough to stick. Either of = these blocked-flow possibilities would produce another effect: no heat. = Were you getting heat?