Yes, automobile engineer are eligible for Mtech thermal in IIT. 

Eligibility for M.Tech in thermal engineering :

Candidate having qualified 10+2 from a recognized educational board with physics, chemistry, mathematics as main subjects and a batchlor degree (B.E/ B.Tech) in any of mechanical, automobile, aeronautical engineering or equivalent discipline, with a minimum aggregate score of 55% are eligible to apply for M.Tech thermal engineering courses. This percentage criterion, however may vary across various institute.

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All the best !!

Hello Sir. Yes they are. Candidates having qualified 10+2 from a recognized educational Board with Physics, Chemistry & Math as main subjects and a Bachelor's degree (B.E./ B. Tech) in any ofMechanical, Automobile, and Aeronauticalengineering, or equivalent discipline, with a minimum aggregate score of 55% are eligibleto apply for M.Tech.