Comprehensive auto insurance coverage/definition of mechanical breakdown exclusion

Comprehensive does not include any type of mechanical breakdown.  Period.

Cars will, over time, undergo wear and tear, which includes mechanical breakdown. Insurance does not cover the inevitable deterioration of the car; the maintenance of your car is your own responsibility.  Mechanical breakdown is not, therefore, included in your comprehensive coverage. However, some car insurance companies will allow you to specifically purchase mechanical breakdown insurance as part of your policy.