Hear hear!
I've personally come to consider them a wear item...they can fail suddenly but also just tend to gradually degrade over time as the internal wax pellet ages.
Not possible to see on the factory gauge because it's programmed to show straight up (90C in Canada) for a wide range of actual temps, but with an actual coolant monitor like a Scan Gauge over the years the engine slowly takes longer to come to full operating temp *and* "full operating temp gets lower and lower, particularly in the winter.
My current BEW generally got to about 84C at best when I first bought it a few years ago...shrugged it off as normal for the car...but last season it was more common to see 82C, and this season 78C unless I pushed her hard. All the while the dash reads 90.
New 87C factory stat...wow....back to a perfect 88C under all driving conditions *and* up to that temp in what seems like half the time. Dash still reads 90.
Old stat looked fine, opened and closed properly in a pan of boiling water, etc.
Too soon to tell, and we are on winter diesel ATM, but I know I will be seeing a lift in fuel economy too, having added nearly 10C to the average operating temp and also getting there sooner.
$35 bucks Canadian for a good t-stat and housing plus an extra half hour during a timing belt when the system is already drained...sure they say don't fix it if it ain't broke, but without a Scan Gauge being watched nerd-like you may not be aware it's slowly dying.
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