Replace Heater Core
How to Replace a Heater CoreYour vehicle’s heater core is a very important component of the
heating system, especially when temperatures
drop. The heater core is nothing more than a small radiator located in your vehicle’s
HVAC system which hot coolant from the engine’s cooling system circulates through.
When the heater core gets hot, the blower motor fans air through it and into the
vehicle allowing you to control the inside temperature and defrost the windshield.The most common cause of heater core
problems is usually neglect. Cooling systems need to be serviced on a regular
basis. If they are not, the coolant can become corrosive, and will cause deterioration
from the inside out. A heater core can be bad in two ways, plugged or it may develop a leak. To check
for plugging, start the vehicle, allow it to warm up to normal operating temperature,
and turn the heater on high. Next, feel both heater core hoses. Both should become
hot. If only one becomes hot, chances are the core is plugged and not allowing coolant
to pass through it. If this is the case, you may be able to back flush the core
and clean it so it works again. If both hoses are hot and you still have no heat,
check and repair the blend air door.
When a heater core develops a leak, there are usually two ways to know. First, you may see steam coming from the vents in the vehicle. The steam will usually have a sweet smell to it and becomes very hard to clean from the windows. Second, often times the heater core will leak coolant. When this happens, you will most likely notice that the passenger side floor is wet from leaking coolant.Regardless, replacement of a heater core can be very expensive due to the amount of labor required. When replacement is required, we recommend that you purchase a quality heater core. Inexpensive ones usually don’t hold up too well and you won’t want to do it a second time.
Parts and Supplies needed to replace a Heater Core1. New heater core2. Coolant3. New hose clamps for the heater core hoses
4. New heater hose if you plan to replace it5. Protective clothing6. A large pan to collect used coolant7. Eye protection
Tools Needed to Complete this Job1. Socket wrench set
2. Wrench Set3. Screw driver set
InstructionsStep 1 - Park the vehicle on a flat surface, place it in park, and disconnect the negative terminal from the battery, and remove the air bag fuse if applicable.Step 2 - Take a large pan or bucket and drain the radiator coolant. There will be a drain at the bottom of the radiator that appears to be a wing nut. Turn it clockwise and allow the coolant to fully drain.Step 3 - Once the coolant has drained, carefully remove the coolant and place it in a safe place. If it isn’t more than two years old, it can be reused. NOTE: Animals are attracted to coolant. If they consume coolant, it can kill them, so keep it out of reach.Step 4 - Remove the two heater core hoses that are attached to the heater core at the firewall of the vehicle. Step 5 - Move to the inside of the vehicle, open the glove box, and remove the glove box compartment.Step 6 - Under the dashboard, remove any protective panels that block access. Often times they are screwed into place, so look for screws.Step 7 - Next, you need to remove the HVAC duct work. Pay close attention while removing parts so you can reinstall them correctly at a later time.Step 8 - The Duct work is plastic. Where it joins together, the two components slide together. However, you need to locate mounting screws and remove them for it to come apart and out. Remove all duct work including windshield duct, air distribution duct, and any other that you see.Step 9 - Check and remove any under dash panel lights that are attached to the dash.Step 10 - Next, locate all instrument panel to tie bars and body screws and remove them. After all screws are removed, carefully remove the dashboard assembly.Step 11 - Now you have access to the heater core box.Step 12 - Disconnect the blower motor wiring, remove the screws from the heater core box, and remove the blower motor. Step 13 - Next, locate the heater core inside the heater core box. The heater core retainer bolts are usually located in a recess at the center of the heater core cover. Remove the retainers.Step 14 - Carefully remove the heater core keeping the steel tubes facing upward to prevent coolant from leaking into the vehicle.Step 15 - Clean and inspect the heater box to make sure seals and gaskets are in good condition and reusable.Step 16 - Install the new heater core back into the box.Step 17 - Clamp the new heater core in place.Step 18 - Replace the heater core cover and tighten.Step 19 - Replace the blower motor, replace screws, and replace wiring harness.Step 20 - Carefully, install the dashboard back into position and attach it to the tie bars and body.Step 21 - Replace any under dash lights that were removed.Step 22 - Replace all duct work and reattach, and replace all other items such as the radio, trim panels, trim plates…Step 23 - Once the dash is replaced, attach the heater core hoses under the hood of the vehicle. NOTE: This is a good time to replace heater hoses and clamps.Step 24 - Refill the cooling system. Step 25 - Install the air bag fuse and then reattach the negative battery terminal.Step 26 - Turn the heater on high and start the engine.Step 27 - Allow the engine to reach operating temperature and check for leaks. NOTE: It isn’t uncommon for there to be trapped air in the system that will cause problems such as no heat, overheating… It this is the case, many vehicles have a bleeder valve to allow trapped air to escape located near or on the thermostat housing. If there isn’t one, slightly loosen the return line from the heater core to allow air to escape. PLEASE NOTE: Coolant gets extremely hot. Do this when the vehicle's engine is cold.
Best Practices
When a heater core develops a leak, there are usually two ways to know. First, you may see steam coming from the vents in the vehicle. The steam will usually have a sweet smell to it and becomes very hard to clean from the windows. Second, often times the heater core will leak coolant. When this happens, you will most likely notice that the passenger side floor is wet from leaking coolant.Regardless, replacement of a heater core can be very expensive due to the amount of labor required. When replacement is required, we recommend that you purchase a quality heater core. Inexpensive ones usually don’t hold up too well and you won’t want to do it a second time.
Parts and Supplies needed to replace a Heater Core1. New heater core2. Coolant3. New hose clamps for the heater core hoses
4. New heater hose if you plan to replace it5. Protective clothing6. A large pan to collect used coolant7. Eye protection
Tools Needed to Complete this Job1. Socket wrench set
2. Wrench Set3. Screw driver set
InstructionsStep 1 - Park the vehicle on a flat surface, place it in park, and disconnect the negative terminal from the battery, and remove the air bag fuse if applicable.Step 2 - Take a large pan or bucket and drain the radiator coolant. There will be a drain at the bottom of the radiator that appears to be a wing nut. Turn it clockwise and allow the coolant to fully drain.Step 3 - Once the coolant has drained, carefully remove the coolant and place it in a safe place. If it isn’t more than two years old, it can be reused. NOTE: Animals are attracted to coolant. If they consume coolant, it can kill them, so keep it out of reach.Step 4 - Remove the two heater core hoses that are attached to the heater core at the firewall of the vehicle. Step 5 - Move to the inside of the vehicle, open the glove box, and remove the glove box compartment.Step 6 - Under the dashboard, remove any protective panels that block access. Often times they are screwed into place, so look for screws.Step 7 - Next, you need to remove the HVAC duct work. Pay close attention while removing parts so you can reinstall them correctly at a later time.Step 8 - The Duct work is plastic. Where it joins together, the two components slide together. However, you need to locate mounting screws and remove them for it to come apart and out. Remove all duct work including windshield duct, air distribution duct, and any other that you see.Step 9 - Check and remove any under dash panel lights that are attached to the dash.Step 10 - Next, locate all instrument panel to tie bars and body screws and remove them. After all screws are removed, carefully remove the dashboard assembly.Step 11 - Now you have access to the heater core box.Step 12 - Disconnect the blower motor wiring, remove the screws from the heater core box, and remove the blower motor. Step 13 - Next, locate the heater core inside the heater core box. The heater core retainer bolts are usually located in a recess at the center of the heater core cover. Remove the retainers.Step 14 - Carefully remove the heater core keeping the steel tubes facing upward to prevent coolant from leaking into the vehicle.Step 15 - Clean and inspect the heater box to make sure seals and gaskets are in good condition and reusable.Step 16 - Install the new heater core back into the box.Step 17 - Clamp the new heater core in place.Step 18 - Replace the heater core cover and tighten.Step 19 - Replace the blower motor, replace screws, and replace wiring harness.Step 20 - Carefully, install the dashboard back into position and attach it to the tie bars and body.Step 21 - Replace any under dash lights that were removed.Step 22 - Replace all duct work and reattach, and replace all other items such as the radio, trim panels, trim plates…Step 23 - Once the dash is replaced, attach the heater core hoses under the hood of the vehicle. NOTE: This is a good time to replace heater hoses and clamps.Step 24 - Refill the cooling system. Step 25 - Install the air bag fuse and then reattach the negative battery terminal.Step 26 - Turn the heater on high and start the engine.Step 27 - Allow the engine to reach operating temperature and check for leaks. NOTE: It isn’t uncommon for there to be trapped air in the system that will cause problems such as no heat, overheating… It this is the case, many vehicles have a bleeder valve to allow trapped air to escape located near or on the thermostat housing. If there isn’t one, slightly loosen the return line from the heater core to allow air to escape. PLEASE NOTE: Coolant gets extremely hot. Do this when the vehicle's engine is cold.
Best Practices
- Never work on the vehicles cooling system when the engine is hot.
- When replacing the heater core, always purchase a quality part.
- Inexpensive or used heater cores will need to be replaced sooner.
- We recommend replacement of heater hoses and clamps at this time.
- After disconnecting the battery, always allow a minimum of 10 minutes before working around the air bag system.
- Ensure the roundness of the heater core hose fittings to help provide a proper seal.