Leaking heater core

A leaking heater core will reduce the level of coolant and hinder heater operation. It can also pass small amount of coolant into the interior of the vehicle.

Table of Contents

• 1. Symptoms
  • 1.1 Windshield Fogs Up When Heater is On
  • 1.2 Heater Blows Cold Air
  • 1.3 Interior Smells Like Coolant
  • 1.4 Vehicle Leaks Coolant

Symptoms

Windshield Fogs Up When Heater is On

Coolant that is collected by the air passing through the core will vaporize. As it come into contact with the cool glass, it will condense and fog up the window.

Heater Blows Cold Air

A leaking heater core may not be able to transfer the heat of the coolant. Depending on the location of th leak, the heat may be reduced or diminished completely.

If the leak is at the point where the coolant enter the core, the air passing through it may not be heated enough. It also may contain small amounts of coolant as it enters the passenger cabin.

If the leak is where the coolant exits the core, the heater may still blow warm air, but the coolant level will fall, leading to little or no coolant flowing through the core.

Interior Smells Like Coolant

If there is a smell inside the vehicle when the heater is on, this may be caused by small amounts of coolant being carried into the passenger cabin. As the air passes through the heater core, it picks up small amounts of coolant from a leak. The air then enters the passenger compartment.

Vehicle Leaks Coolant

The heater core is a possible source of coolant leaks.