Quote:
Originally Posted by trebuchet03
If it leaks, it's poisonous gas leaking in the cabin versus engine coolant 
That, and it's a whole lot easier to route a relatively clean liquid than a much hotter gas |
both good answers, I will also add.
-heat is exchanged easier, and more efficiently in a fluid
-antifreeze has an anti corrosive that should ideally keep the system working properly longer
-exhaust is wizzing out of your car as fast as possible, back pressure makes your car perform less goodish, where as the radiator fluid is restricted/slowed down by the therm to make the engine coolant exchange work better, and it doesn't _really_ effect engine performance.