Chrysler 300M no heat issue despite replacing thermostat, actuator, and water pump, and system flush on Chrysler 300M

Submitted by Vehicle Owner · Jun 23, 2025
Published by RepairPal

Problem overview

Some Chrysler 300M owners report experiencing no heat issues even after replacing the thermostat, actuator, and water pump, as well as flushing the system. These problems may stem from inadequate coolant levels, which can hinder proper circulation to the heater core. Additionally, despite a new thermostat being installed, it could still be defective, affecting engine temperature regulation. Owners also note that a partially plugged heater core might restrict hot coolant flow, leading to insufficient heat. A malfunctioning blend door actuator can disrupt airflow and temperature control within the cabin, further complicating the issue. Some owners find that cycling the Automatic Temperature Control (ATC) or performing a battery disconnect can help reset the HVAC system and restore heat functionality. It is important for owners to systematically check these components to effectively troubleshoot and resolve the no heat problem.

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