Wordnet 3.0
VERB (2)
1. 
 get excessively and undesirably hot; 
- Example: "The car engines overheated"2. 
 make excessively or undesirably hot; 
- Example: "The room was overheated"
The Collaborative International Dictionary of English v.0.48:
Overheat \O`ver*heat"\, v. t. [Cf. Superheat.]
   To heat to excess; to superheat. --Cowper.
   [1913 Webster]
WordNet (r) 3.0 (2006):
overheat
    v 1: get excessively and undesirably hot; "The car engines
         overheated"
    2: make excessively or undesirably hot; "The room was
       overheated"