Fuel Efficiency and the Yaris

[sbergman27]

Originally Posted by Hershey

Also try to leave the heater core on cold to cut off flow of antifreeze to speed up the use of 4th gear . Then turn on heat if needed .

Note that this practice makes a *substantial* difference. Even in relatively mild winter weather, say 50F, the Yaris is unable to maintain a coolant temperature of more than about 155F at idle with the heater on high. It's 30F here right now and I just got back from a trip to Walmart. I know from experience that with the heater off, the engine reaches 130F and the "cool" light goes off before I get to the Walmart parking lot. This morning, I left the heater on high. It didn't hit 130F until I was almost *back home* on the return trip. And when I pulled into my parking space, the temp was 136F. That's still 4 degrees shy of when the transmission would have made 4th gear and converter locking available. (And the interior wasn't exactly toasty yet.)

The heater on the Yaris can accurately be considered an auxiliary radiator.

-Steve