  Millimetre-band scans of the frequency space towards optically dim quasars is
potentially a highly efficient method for detecting new high redshift molecular
absorption systems. Here we describe scans towards 7 quasars over wide
bandwidths (up to 23 GHz) with sensitivity limits sufficient to detect the 4
redshifted absorbers already known. With wider frequency bands, highly
efficient searches of large numbers of possibly obscured objects will yield
many new molecular absorbers.
