texture mapped surface not shown and hidden correctly

as I rotate the scene my texture mapped polygon should be hidden, other times it is hidden correctly. Maybe hidden surface removal is not working, but, I have used glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); before drawing, and glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH); and glEnable(GL_DEPTH_TEST); in main().
How do I fix this?

Greatly appreciate any help.

(I am drawing a GL_QUAD, a cube with four faces, without top and bottom. One of the faces is texture mapped. So when rotating the other faces of this quad should cover that face, now showing the reverse side of the texture image, but that reversed texture image should not be showing through. the image is a tga file)

[This message has been edited by hakko (edited 11-29-2001).]