How to Unclog the Heater Core of Newer Model Cars

How to Unclog the Heater Core of Newer Model Cars

First, I thank my husband for being so kind as to answer all my questions when he tackled this repair. As you can imagine, having your car’s heater go out, during the winter, while living in Northeast Ohio, could not possibly occur at a more inconvenient time. But, here we are. Unclogging the heater core to restore the heat function of your car is really quite a simple process.

Part I: Locating the Heater Core and its Removal

Locating the Heater Core and its Removal

Disconnect both the supply and return hoses at the firewall. The firewall is the flat wall located in the engine compartment, under the window shield. Next, remove all necessary panels from the dashboard and center console, if so equipped, and the glove-box. Be careful of any wires or control cables while doing so. First, locate the heater core housing. It will be rectangular in shape and most often black in color. Next, remove the screws or retaining clips on the cover and the heater core should pull or lift out. Some models may require that the air conditioning unit be discharged because the A/C Evaporator is sometimes located in the same compartment as the heater core. If this is the case, the connecting hoses must be disconnected and the whole housing must be removed from the vehicle to lift out the heater core.

Part II: Is it functioning correctly?

To determine if the heater core itself is faulty, when removing, it may leak anti-freeze on the car’s interior, passenger floor area. There may be a distinct odor of anti-freeze or an antifreeze mist on the windows. If any of these occur, a new one will have to be purchased a new heater core. A heater core usually ranges in price from $60 to $150, depending on the make and model of the car. If the heater core is just clogged, it is very easy to check here. Simply try to run water through using a hose or in a wash tub sink. Trying to blow air through it using an air compressor will work, too.

Part III: Eliminate The Clog From The Heater Core

Not all work areas are the same, but these steps can be adapted to fit the situation. A heated garage to work in, though, sure makes it a lot easier. Connect a small hose to the faucet on a utility tub, insert the open end of the hose into the supply end of the heater core, which is usually the top or the larger of the two lines. Using water that is very hot, blast it through the hole to gage how badly the heater core is clogged. If there is flow that contains a lot of gunk, rusty water or other debris, keep blasting the water through until it runs clear and it shooting out at a good pace. It is possible that there might be a major clog in the heater core if there is hardly any flow of water. If this is the case, there are two things that most households have on hand to help in breaking up the clog. White Vinegar or CLR (Calcium, Lime & Rust Remover): Pour one of these items in both ends of the heater core, fill it as much as you can, then let the heater core sit in the utility tub or sink for about 30 minutes, allowing the chemicals to break up the clog. Then, flush the heater core with hot water until the water runs clear. These chemicals are acidic so keep safety in mind and wear long sleeves and rubber gloves when handling them. Don’t forget to wear safety glasses or goggles, as well.

Part IV: Putting It All Together And Final Tips

Putting It All Together And Final Tips

Once the heater core is flushed out, has good flow, and clear water coming out, it is time to re-install the heater core and re-connect any lines or hoses that were removed. NOTE! If the A/C had to be discharged, don’t forget to have it re-charged as soon as possible to avoid problems with the A/C when hot weather arrives. Fill up and top off the antifreeze. Start the vehicle and allow it to run until it reaches normal operating temperature. Turn the heat on full-heat position. Finally, turn the blower on and let there be heat!

If you are mechanically handy, have simple hand tools and enjoy working on cars, you just saved some money. Most shops charge anywhere between $150 and $200 to unclog vehicle heater cores. It is also highly recommended that you have on hand a repair manual for your specific vehicle to assist you on how to disassemble and assemble the various parts of the vehicle for while following this procedure to unclog the heater core. Repair manuals can be purchased at any automotive parts store.