One of the basic laws of thermodynamics is that heat flows from a hot object to a cold object.
Heat flows faster,(think leaks faster) from a hot object surrounded by a cold object than it flows from a hot object surrounded by a warm object.
The hot object we are talking about is the hot gases in your engine’s cylinders that have just been heated up by the fuel burned in the cylinders. Every BTU of heat that leaks to the cylinder walls is a BTU of heat that simply increases the entrophy of the world instead of being turned into 778 ft lb of energy by the expanding gasses pushing on the pistons.
That’s why engines need to be hot in order to be efficient. If we could develop engine materials and lubes that could run at 1000 degrees, we could achieve a quantum leap in engine thermodynamic efficiency.
Just remember that every BTU of heat that leaks from the expanding gasses to the cylinder walls is lost energy and ice cold cylinder walls and combustion chambers cool those gasses faster than hot cylinder walls and combustion chambers do.
I believe it. Our '95 Civic mpg goes down from 45 mpg to 40 and our '89 Accord mpg goes down from 35 to 30 during the cold winter months here in Pennsylvania. Same trip . . . about 15% town and 85% highway, checked it many times for both cars, over several years of driving. I attribute it to different gas (although I can’t verify that, but I get my gas at mostly the same places all the time),slower warm-up of the lubricants (engine oil, transmission fluid, gear oil, wheel bearings, etc) a richer mixture due to the cold . . . evident on the '89 because it’s carb’d and you can see/smell it when cold . . not so obvious on the '95 as it is F/I . . . and I just accept it. Our drop in mpg is less than 10% . . . yours is a bit higher, almost 25%. Your question . . EH??? Guess that means “is it possible?” I for one believe it. Maybe a block heater will help with a faster engine oil warm-up, the car should run “leaner” or more normal more quickly. Worth the effort? That’s up to you. Good luck! Rocketman
Circuitsmith was prophetic. I recently got a check engine light, the first ever. Turned out the thermostat was running partly open. I guess it’s been that way awhile, finally got bad enough to trigger the error. Coolant was running at 154 degrees. So, after this thermostat gets replaced we’ll see how much better it does…