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Old 03-23-2019, 10:49 AM   #17 (permalink)
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Red Devil - '11 Honda Insight Elegance
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90 day: 53.73 mpg (US)

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Originally Posted by squirrl22 View Post
Could be, I don't remember if the old mk 2 Jetta heater core was on a separate line from the thermostat.

The big question, is:
Have you had any experience raising the coolant temp to increase MPG? If so, this is the place to share that experience.
He refers to the thermostat that closes off the radiator loop when the engine is cold, not that of the heater core.

If the radiator stat is bad it will even when the engine is not yet warm allow coolant to the radiator which feeds back cold coolant to the engine, preventing it from heating up quickly.
This is indeed very bad for economy. I had this happen in my '85 Civic. I had no economy readout back then, but it made itself felt at the pump.
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.14 Gm or 0.09 MM.

Last edited by RedDevil; 03-23-2019 at 07:20 PM..
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