> >
> >Rather, the coolant stays in the main coolant reservoir (the more-spherical,
> >less squarish-one on the corner of the engine compartment near the left rear
> >blinkers).
>   
> When the coolant gets hot it expands into the expansion tank. When it cools
> down after the engine is shut off, the coolant is sucked out of the
> expansion tank and back into the main reservoir. Whether hot or cold, the
> expansion tank should never be empty.
> 
      TO ADD TO that:   If you have air in the system, it will expand
      much more than liquid, forcing much more coolant out, (and hopfully
      air). As it cools, it will then suck in coolant, thus "self purging".

                               Eric Zeno