A vent plug and method are provide for isolating a feature of a part. The vent plug includes a plug receivable in an opening in the part to form an airtight seal between the plug and the surface of the part. A stem is receivable in a bore through the plug. The stem includes a cap and a collar. The cap has a sealing surface extending radially from an outer surface of the stem and engageable with a first surface of the plug such that sealing surface overlaps a vent hole extending through the plug. The collar extends radially from the outer surface of the stem and captures the plug between the collar and the cap.