After starting the engine, what should the coolant temperature gauge do?

After starting the engine, what should the coolant temperature gauge do?

• A. Rise to maximum immediately
• B. Begin to gradually rise to normal
• C. Stay at zero
• D. Drop to minimum

Answer: (B)

The coolant temperature gauge should begin to gradually rise toward the normal operating range after you start the engine. When the engine is cold, the thermostat restricts flow, and as the engine warms, the coolant heats up and the gauge climbs into the normal range. It should not jump to the maximum or stay at zero or drop to minimum. A rapid rise to maximum would suggest overheating or a faulty gauge, while a gauge at zero or minimum could indicate a sensor or wiring issue or that the engine isn’t warming properly. In normal operation, you’ll see a steady, gradual climb to and maintenance within the normal range as the engine reaches operating temperature.

The coolant temperature gauge should begin to gradually rise toward the normal operating range after you start the engine. When the engine is cold, the thermostat restricts flow, and as the engine warms, the coolant heats up and the gauge climbs into the normal range. It should not jump to the maximum or stay at zero or drop to minimum. A rapid rise to maximum would suggest overheating or a faulty gauge, while a gauge at zero or minimum could indicate a sensor or wiring issue or that the engine isn’t warming properly. In normal operation, you’ll see a steady, gradual climb to and maintenance within the normal range as the engine reaches operating temperature.