No, your auto insurance would not cover a mechanical issue such as a blown engine that was not caused by a covered loss per the terms of your auto insurance policy, such as a car accident.

You can check with your state's consumer protection agency to see what your state's laws are regarding this type of situation if you believe the mechanic repairing your vehicle was at fault. If the repair shop was at fault in some way for blowing your engine than they should be held liable and thus you may want to seek legal counsel to see what your recourse could be.

Other options would be if your car was purchased with a warranty or mechanical breakdown insurance policy then you may be able to put a claim through this they of policy for the engine.

Coverage for specific parts of your vehicle, such as the engine or transmission, to be repaired or replaced is usually done with by means of a warranty and is not covered under your personal auto insurance policy. Warranties can be purchased at dealerships, financial institutes or online.

Some financial entities also offer mechanical breakdown insurance which would cover mechanical issues with your vehicle. If you believe you purchased this when you got financing for the car then contact your lien holder to get information on the breakdown insurance provider through which you could make a claim.