A blow mold shell assembly includes a mold cavity insert defining a mold profile on an inner surface. A manifold insert is separately formed from the mold cavity insert and disposed outboard of the mold cavity insert. The manifold insert includes at least one coolant channel formed therein. The mold cavity insert is substantially solid throughout its cross-section and precluded from passing coolant. In one example, the coolant channels may be formed longitudinally through the manifold insert. A fluid inlet fitting and a fluid outlet fitting are both in fluid communication with the manifold insert.