Abstract: The combination of a dipstick and plug assembly adapted to be inserted within a standard oil filler tube of an engine. In a preferred embodiment, the assembly includes a molded cap element having an integrally formed handle for facilitating gripping thereof. Positioned underneath the cap element is a preferably separately formed, molded cylindrical body which is adapted to be fitted within the oil filler tube. The dipstick comprises a blade member which extends through an aperture in the cylindrical body and is embedded within the cap element. The cylindrical body has a pair of O-rings extending peripherally thereabout. The upper O-ring is integrally molded with the body and serves as a sealing means for the tube. The lower O-ring comprises a separately formed, flexible O-ring which is disposed within a groove formed in the cylindrical body and is adapted to facilitate the insertion and withdrawal of the assembly in the filler tube.