Thermostat Stuck?

[prostwest]

Posted here because it's the OTM, 1999 Caravan.

Got it in the summer, first time driving it in cold weather. In more temperate weather, Scanguage has showed max around 208°, and net research shows OE thermostat is 180°. Last night Scanguage read 53° fWT on startup. Within a couple blocks had climbed to about 100°, then I got on hwy. Maxed at mid to high 120°s, wavering, on 10 mile hwy stretch, then climbed to 150°s in 10 blocks of stop/start.

I'm thinking themostat is stuck open and I better damn well fix it before weather gets really cold. Confirmation?

[ChristianL]

I would concur. My Corolla did the same thing last winter, and it turned out to be a bad thermostat.

As an amusing aside, a friend of mine (who knows nothing about cars) drove an old Subaru when he was living in Iowa (where it gets VERY cold in the winter). He drove it through the fall, and into winter and always figured, "Oh hey, the heater doesn't work very well on these cars."

Then one day by chance, a mechanic removed the radiator cap only to discover there was zero liquid in there. Apparently, the cold weather was enough to keep the engine temperate, and after adding a 50/50 mix to the radiator, "I had heat!"

[prostwest]

Neat- I wonder if the water pump impeller blew enough of the radiator-fridged air through the passages to take the edge off combustion chamber heat.