An engine cooling system operating at the correct temperature with a properly operating thermostat is necessary for the heater to be effective.

Question

Quizplus · Accepted Answer

The engine cooling system regulates the temperature of the engine and also provides heat to the cabin through the heater core. If the engine is not operating at the correct temperature, or if the thermostat is not functioning properly, then the heater may not work effectively.

An Engine Cooling System Operating at the Correct Temperature with a Properly