I don't know if this has been covered before, but how effective is it to drive with the heater on? I heard if you are ever stuck in tariffic you should just turn on your heater on full blast. How much temp difference are we looking at under the hood?

 

The heater is in essence another radiator. By running the heat full blast you can help control coolant temps. I use it on occasion during hot summers on the track but other than that I mever worry about it.