An access device for placing a medical article within a body space, the access device comprising: a dilator comprising: an elongated dilator body, and a dilator hub extending from the elongated dilator body, the dilator hub defining an inner cavity having a distal cavity portion and a proximal cavity portion; characterized in that the access device further comprises; a valve element made of a single unitary body having an open position and a closed position, the valve element comprising: an attachment portion configured to be supported by the dilator hub, and a sealing portion extending radially inwardly from a side of the inner cavity, the sealing portion being biased toward the closed position, wherein the valve element is configured to inhibit fluid flow between the distal cavity portion and the proximal cavity portion when the valve element is in the closed position, and wherein the valve element comprises an elastomeric material and/or flexible structure capable of deformation or movement as a guidewire abuts against and extends through the valve element permitting movement of the guidewire through the dilator hub in a proximal direction relative to the dilator wherein the sealing portion comprises a first sealing surface, wherein the dilator hub comprises a second sealing surface, and wherein the first sealing surface is against the second sealing surface to substantially seal the distal cavity portion from the proximal cavity portion when the valve element is in the closed position. a dilator comprising: an elongated dilator body, and a dilator hub extending from the elongated dilator body, the dilator hub defining an inner cavity having a distal cavity portion and a proximal cavity portion; an elongated dilator body, and a dilator hub extending from the elongated dilator body, the dilator hub defining an inner cavity having a distal cavity portion and a proximal cavity portion; characterized in that the access device further comprises; a valve element made of a single unitary body having an open position and a closed position, the valve element comprising: an attachment portion configured to be supported by the dilator hub, and a sealing portion extending radially inwardly from a side of the inner cavity, the sealing portion being biased toward the closed position, wherein the valve element is configured to inhibit fluid flow between the distal cavity portion and the proximal cavity portion when the valve element is in the closed position, and wherein the valve element comprises an elastomeric material and/or flexible structure capable of deformation or movement as a guidewire abuts against and extends through the valve element permitting movement of the guidewire through the dilator hub in a proximal direction relative to the dilator wherein the sealing portion comprises a first sealing surface, an attachment portion configured to be supported by the dilator hub, and a sealing portion extending radially inwardly from a side of the inner cavity, the sealing portion being biased toward the closed position, wherein the valve element is configured to inhibit fluid flow between the distal cavity portion and the proximal cavity portion when the valve element is in the closed position, and wherein the valve element comprises an elastomeric material and/or flexible structure capable of deformation or movement as a guidewire abuts against and extends through the valve element permitting movement of the guidewire through the dilator hub in a proximal direction relative to the dilator wherein the sealing portion comprises a first sealing surface, wherein the dilator hub comprises a second sealing surface, and wherein the first sealing surface is against the second sealing surface to substantially seal the distal cavity portion from the proximal cavity portion when the valve element is in the closed position.