How to Change the Heater Core in a Car

  • 1-6 hours
  • Beginner
  • 45-100
What You'll Need
New Heater Core
Wrench kit
What You'll Need
New Heater Core
Wrench kit

If there is coolant leaking from your motor, you may need to learn how to change the heater core of your car. The heater core is like a radiator in that it balances the temperature of your vehicle. The radiator cools your engine when it is too warm and the heater core heats up car interior when it is too cool.

Step 1: Determine that the Heater Core is Broken

There are two things that could occur that will let you know that the heater core is not working. First, there will be a leak under your car approximately under your dashboard, second there will be no hot air blowing when you turn on your heater.

Step 2: Find Your Heater Core

Finding your heater core can be tricky as it is different with every car. You can look up the location for your car in a repair manual or try to find it online. Once you know the general area, you should be able to find it and remove it yourself.

Step 3: Purchasing a New Heater Core

Make sure that you know the make, model and year of your car before attempting to purchase a new heater core. You should be able to purchase or order one from your local car parts store. Though you may be able to find a used part, it may not be as reliable and you may have to replace it.

Step 4: Cool Your Engine

Do not attempt this process while your engine is warm, as it could cause you burn injuries or cause more problems for your engine. If you have been using your vehicle, place it in a shaded area and allow it to cool for 30 minutes to an hour. If you would like to speed up the process, you may open the car hood, as long as there is no direct sun shining onto your engine.

Step 5: Remove Old Heater Core

Lift up your car hood and locate the heater core. If you need to remove other parts of your engine, do it carefully according to the instructions in your repair manual. Notice how things were attached so that replacing the parts will be easier.

Some makes of cars have the heater core under the dash inside car. This location can be a real problem to service and might be more than you care to attempt. If this is the situation, then a mechanic shop might be the answer.

When you find the heater core, use a screwdriver and/or wrenches to remove the screws and bolts that keep it in place. Locate and disconnect both the intake and the outtake hoses that are connected to the core and slowly lift it out, making sure not to spill any coolant that may still be in it.

Step 6: Attach the New Heater Core

Attach the new heater core in the opposite way you removed the old one. Make sure that the intake and outtake hoses are reconnected to the core, connect each one to the proper area to ensure that it will not leak.

Screw the new heater core into place, making sure that it is secure. After the heater core is properly installed, replace any other engine parts that you had to remove.

Replacing your heater core yourself can save you a lot of money that you would have otherwise spent at a repair shop. Though it may be a little tricky to do it the first time, you will have the knowledge if the problem ever arises again in the future.