Posted on January 20, 2009 - by Richard

Heater Core Basics Made Simple

Understanding heater core basics is quite important specially during winter times when we need heat inside our vehicles. This blog post will show you how this heating device works so you can drive your vehicle without freezing during cold weather. The heater core technology is based on the design of a radiator: the heat exchange process which comes from the engine coolant which is transferred to the fins wrapped around the heater core tubes. If the blower fan blows into the fins, heated air is then sent to the vehicle compartment.

Looking closer at heater core basics, the heater core is located under the dash panel. It is constructed of aluminum for maximum exchange transfer ability. The heater core is incase in a light plastic box and is connected to a series of ducting and shutter doors which can be used for air distribution inside the vehicle. If the vehicle has air conditioning, those ducting can be closed when the heat from the heater core is not being used.

Controlling the heat entering the heater core is done thru the heater control valve which can be adjusted in the dash panel. If your vehicle is older, the control could done by mechanical cable linkage or vacuum connections to open and close the air doors. Lately, the control is done by electronics devices if you have a newer vehicle. Control is done by limiting the coolant entering the heater core or closing the air duct doors or passages of heated air. On some heater core set up, the vehicle is fitted with 2 heater cores which allows both the driver and passenger vehicle compartments to control the temperature setting.

Heater core basics TIPS:

If you are not getting enough heat from your heater core, open up your engine compartment and follow the 2 hoses connected to the heater core in the firewall. Both the coolant inlet and outlet hoses are connected from the engine cooling system to the heater core itself. These same hoses can be used to check the condition of the heater core operation:

1.) If both hoses are hot when the heater is turned on, it shows the heat transfer inside the heater core is complete. Otherwise, if one of them is cold, it means the coolant is being blocked or restricted. This problem requires checking the heater control valve or replacing a clogged heater core passages.

2.) If both coolant hoses are cold, it means the engine is not producing heat which could be attributed to low coolant level, a thermostat stuck open or a water pump circulation failure…etc.

3.) If the heater core is suspected to be cracked, look underneath at the floor carpet in the passenger side and find traces of coolant. A lot of times, a cracked heater core will cause fogging in the windshield and a strong smell of coolant.

4.) If the vehicle has an air conditioning, it is better to leave this job to a garage if you have not done it before. There are lots of special tools you need and some electronics components could be damaged like sudden deployment of your airbags. The airbag can still work with battery disconnected and cause serious injury.

Heater core removal and installations for non AC vehicles and without airbags:

1.) wait till the engine coolant has completely cooled off.
2.) Disconnect the battery terminal negative connections.
3.) Drain the coolant and disconnect the coolant hoses in the firewall.
4.) Depending on the vehicle’s model, the heater core can be removed under the passenger side by following the technical instruction from vehicle’s manufacturer. Never attempt to do this without reading the instructions to prevent unnecessary damage to other dash components.
5.) On most vehicles, the heater core plastic assembly can be taken out so you can split it and replace the heater core inside.
6.) To install the heater core is the reverse of the above procedures. use the right coolant mix which is usually 50-50 anti-freeze and water or check your vehicle manual.

If you need more information about this heater core basics, please leave your comment at the box below.