Trying to verify the orientation of the Vacuum Check Valve on a 1990 740 turbo. I am assuming that the black side points to the manifold and the white side is the outbut to the firewall. I think there are arrow indicators on the white portion pointing to the motor (its labled motor). For some reason, the one in my car was installed in reverse.

I cant tell what is what in the pic in the heating and cooling faq
but it seems clear from ipd's site pic that the black side is manifold.

Michael