Which of the following is a common symptom of a failing battery?

A common symptom of a failing battery is slow engine cranking. When a battery starts to fail, it may not hold a charge effectively, leading to a reduced ability to deliver the necessary power required for starting the engine. This can manifest as a sluggish or slow cranking sound when attempting to start the vehicle.

In contrast, the other symptoms listed are typically associated with different automotive issues; for instance, engine overheating is usually linked to cooling system problems, squeaking brakes suggest issues with the braking system such as worn pads or lack of lubrication, and excessive exhaust smoke may indicate engine problems such as oil burning or fuel mixture issues. Each of these conditions points to a failure in specific components of the vehicle, while slow engine cranking is directly tied to battery performance.