So: how far can you P&G / CODFISH from a cold start in city driving without a water pump belt before the engine reaches operating temperature?
Answer: about 7.5 miles. (Ask me how I know.)
79.9 mpg (US) r.t. local driving in the pouring rain (otherwise I would have biked). It's the first time I've used the car since last weekend when my bungee water pump belt flew off. I forgot to replace it.
I didn't overheat - engine only reached a max of 190 F, where 192 is my normal. But I was wondering why I wasn't getting any heat out of the defroster after the temp gauge started rising near the end of my errands. Then the proverbial light bulb went on!
I wonder how much fuel I saved by not spinning the water pump uselessly for those 7.5 miles.
My gaslog 90-day figure is going to start sucking when the EV is finished and a larger proportion of my Blackfly driving shifts to highway use.
Pretty sure I brought it up on another occasion, but the old-time Model T's and such had no water pumps- just a simple "thermosiphon" system that relied on a tall radiator and the principle that hot water rises to the top and as it was cooled by the radiator it circulates throughout the system. Perhaps removal of the thermostat and water pump would remove restrictions to that free flow and work with such a lightly loaded engine?
But yes I would imagine an electric pump would work, they are known and proven, but it does draw power.
Old EPA 23/33/27
New EPA 21/30/24
You better think about the hot spots in the engine head without water moving around. How about a wind turbine on the water pump - if you vent to the front grill you should be able to get enough air flow to make it spin at moderate speeds.