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Old 01-24-2008, 11:37 AM   #2 (permalink)
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,461

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 55.97 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car - '14 Mitsubishi Mirage ES (base)
90 day: 67.41 mpg (US)
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The guy's right: the coolant shouldn't circulate until the engine has warmed up. That said, I've heard before that the Metro will slowly fall from normal operating temps when idling on a really cold day, like you describe.

That doesn't necessarily mean the t-stat is faulty though. It's possible the engine just doesn't generate enough heat @ idle (0.5 litres per hour is what I measured with mine fully warmed up).

One method of testing the t-stat that comes to mind is opening the rad cap when cold, starting the engine and watching to see if the coolant circulates when the engine is revved. You should be able to tell when the t-stat opens, because the coolant level will change noticeably & it will start flowing.

Mod idea: What about a fire proof insulation blanket you can place on top of the engine, or attach to the hood to keep more heat in the engine compartment?
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