Some people question how much a radiator block helps the car warm-up, since the thermostat is supposed to keep water from going to the radiator when cold anyway.

But I PROMISE it DOES keep the car warmer, longer, like you say, when you make stops, or even when you are in EV, it keeps EV longer. Once the car is hot, it helps keep it hot longer.

I wouldn't drive w/o one in winter personally!
-John