Heater Core

The heater core is the part of the coolant system that is responsible for providing a sufficient and an adequate amount of heat to come through the vents on the dash, so that the inside of the vehicle feels warm and cozy. The coolant system plays a definite role with the supply of heat for the driver and passengers. Without the cooling system, the heater would not function correctly. Lack of heat coming through the vents indicates a problem with the coolant system that should be immediately investigated. Ignoring the problem will result in an overheated engine.

The heater core looks like a smaller version of a radiator and it rests inside of a heater box underneath or behind the dash. Attached to the heater core is an inlet and outlet pipe. These two pipes travel through the firewall and lead into the engine compartment.

When heater cores fail, they could either be clogged or leaking onto the carpet from underneath the dash. Some vehicles have a spout through the firewall so that in case of a heater core leak, the leak does not get on the carpet, but leaks from a spout in the engine compartment. Also, if the windshield fogs when the defroster is on, then that is an indication that the heater core has failed and should be replaced.

If the heater blows, but does not get hot, then this doesn't necessarily indicate a problem with the heater core. This could be any coolant system leak, blockage, or component failure, and further coolant system diagnostics are required.

Heater core replacement can vary in time and difficulty depending on the year, make and model of the vehicle. Some heater cores may be relatively simple to find and replace--taking roughly 45 minutes to two hours. Other heater cores my require the removal of the entire dash and can take as long as ten hours to successfully replace.

Click here to refer to our coolant diagnostic page before coming to the conclusion that your heater core is the only component that has failed. The following are basic step-by-step instructions for the complete removal and installation of the heater core.