Coolant Thermos Question

jillsidious · 01-09-2005, 02:59 PM

Does anyone know excatlly how long the coolant keeps warm in the thermos? Is three days fact or a guess?
What happens after the so called third day? Just a normal start with more emissions?
No speculations please, only fact.
Thanks,
Clint

DaveG · 01-09-2005, 04:00 PM

Lol, well, I suppose it depends on your definition of warm. Is warm "the same temperature as the coolant that went in", or "anything above ambient temperature"?

The thermos just allows the ICE to get up to temperature more rapidly after a cold start. There would be a slight decrease in emissions as presumably the catalytic converter would also warm up faster so it operates at peak efficiency.

Does it matter how long the coolant stays warm for? Obviously, the shorter the timeframe, the warmer the coolant will be and the more benefit you'll get from it.

Dave

Tempus · 01-09-2005, 04:05 PM

Fact: Toyota says 72 hours, I believe the ambient temperature they cite is 20 degrees F.

Fact: Nothing magical happens at the 72 hour point. The coolant doesn't go from "Hot" to "Cold" at the stroke of midnight.

Fact: The coolant will begin to cool the moment you turn the car off, even in the Thermos, so a restart after two hours will result in more fuel being burned than a restart after one hour.

Bottom line, the stored coolant helps make restarts MORE efficient, not totally efficient. That benefit will continue with decreasing effectiveness until the coolant in the Thermos reaches ambient temperature, which is certainly longer than 72 hours.

01-09-2005, 02:59 PM	#1
jillsidious Join Date: Jan 2005 Location: British Columbia Posts: 12 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Coolant Thermos Question Does anyone know excatlly how long the coolant keeps warm in the thermos? Is three days fact or a guess? What happens after the so called third day? Just a normal start with more emissions? No speculations please, only fact. Thanks, Clint

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01-09-2005, 04:00 PM	#2
DaveG Senior Member Join Date: Jan 2004 Location: Vancouver, BC Posts: 807 My Car: 2004 Prius Package: C Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Lol, well, I suppose it depends on your definition of warm. Is warm "the same temperature as the coolant that went in", or "anything above ambient temperature"? The thermos just allows the ICE to get up to temperature more rapidly after a cold start. There would be a slight decrease in emissions as presumably the catalytic converter would also warm up faster so it operates at peak efficiency. Does it matter how long the coolant stays warm for? Obviously, the shorter the timeframe, the warmer the coolant will be and the more benefit you'll get from it. Dave

01-09-2005, 04:05 PM	#3
Tempus Senior Member Join Date: Feb 2004 Location: Washington DC Posts: 1,693 My Car: 2004 Prius Package: #9 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Fact: Toyota says 72 hours, I believe the ambient temperature they cite is 20 degrees F. Fact: Nothing magical happens at the 72 hour point. The coolant doesn't go from "Hot" to "Cold" at the stroke of midnight. Fact: The coolant will begin to cool the moment you turn the car off, even in the Thermos, so a restart after two hours will result in more fuel being burned than a restart after one hour. Bottom line, the stored coolant helps make restarts MORE efficient, not totally efficient. That benefit will continue with decreasing effectiveness until the coolant in the Thermos reaches ambient temperature, which is certainly longer than 72 hours.