Audi A3 1.6 engine hot

[Paul2011*A3*]

Hey guys thinking of buying this Audi on Autotrader. The Ad says they left the engine running for 45minutes to charge s dead battery but it had engine too hot warning light. Anyone had this before or can guess what it could be. Cheers.

http://autotrader.com/used-cars/advert/201141420767780/viewing-23?PHPSESSID=6rv9vi2b6i7q8gp1dvsg37g2a2