IBM 5162 - Documentation Pointers
"An Introduction to the XT Model 286"
Pages 1145-1152 (PDF pages 1177-1184) of Upgrading and Repairing PCs - Tenth Anniversary Edition
IBM manual - 'Technical Reference'
Found at this link
IBM 5162 and 5170 Service Summary
InfoWorld Magazine article (Sep 1986)
"Disk Speed of XT 286 Puzzles Observers"
Computerworld magazine article (Nov 1986)
Discusses apparent lack of demand.
Note that the AT (IBM 5170) used as a comparison is the AT of the time, the 8 MHz version of the AT, not the earlier released 6 MHz models.
PC Magazine article (Feb 1987)
Discusses possible connection to the rumoured 'PC II'.
InfoWorld Magazine article (Jul 1987)
Time of introduction to market, and removal from market.