In a message dated 9/3/2003 6:21:56 PM Eastern Daylight Time,
13brv3@bellsouth.net writes:

> Since water will flow from the engine to the radiator inlet tank, why do
>  they return the heater itself to the radiator outlet side.

The water outlet of the radiator is connected to the suction side of the
pump.  Then there is a greater pressure differential and thus, higher flow volume.

Lynn E. Hanover