A glow plug assembly having a shield integrally connected to a housing is disposed in and retained in a bore in a cylinder head by a clamp connected to the cylinder head. A stop surface connected to said housing is engageable with the cylinder head and establishes the location of a heating element second end in the combustion chamber. The clamp maintains the stop against the head and the orientation of the shield angled second end relative to the combustion chamber. The heating element is connected to the housing by a spacer and the housing is sealed with a filler material which blocks the transfer of fluid through the housing. The filler material maintains the housing from passing fluid between the first and second housing ends, minimizes the vibration of the electrical conductors and conducts the heat out of the glow plug.