Red Seal Automotive Service Technician Practice Exam

Which of the following is NOT a common cause of vehicle overheating?

1. Low coolant levels

2. Faulty spark plugs

3. Malfunctioning thermostat

4. Failed water pump

The correct answer is: Faulty spark plugs

Faulty spark plugs are not a common cause of vehicle overheating. While spark plugs play a critical role in the engine's ignition system by providing the necessary spark to ignite the air-fuel mixture, their failure typically affects engine performance, fuel efficiency, and smooth operation rather than directly causing overheating. In contrast, low coolant levels can lead to inadequate heat transfer, causing the engine to overheat due to insufficient coolant circulation. A malfunctioning thermostat can prevent coolant from flowing to the engine at the correct times, which might lead to overheating if the engine can't maintain its temperature properly. Similarly, a failed water pump would result in a lack of coolant circulation, leading to increased engine temperatures as well. Therefore, the other options are closely associated with the engine's cooling mechanism and directly contribute to overheating issues, while faulty spark plugs do not have that same direct impact.