this would be a mess, wouldn't it:
http://lawnewz.com/opinion/if-hillary-is-indicted-president-clinton-could-pardon-herself-and-congress-might-be-helpless/
I would go with this - a self pardon, even if permissible, would be an impeachable offense:
"There remains a possibility that self-pardon is grounds for impeachment as an abuse of power."