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How To Backflush A Heater Core

Backflush a Heater Core is one of those tasks that seems easy enough, but can quickly become a frustrating ordeal. When your heater core goes bad, it can leave you stranded in the cold. Naturally, you want to get it fixed as soon as possible. But how do you go about doing that? In this blog post, we will walk you through the process of Backflushing a Heater Core. We’ll explain what to do and why it’s important, and we’ll provide step-by-step instructions so that you can backflush your own heater core with ease.

What is a Backflush?

A backflush is a procedure used to clear trapped air from a heater core. The trapped air can cause a number of problems, including poor engine performance and fuel missages. A backflush is typically done when the heater just starts having issues.

How To Do A Backflush On A Heater Core

If your heater core is not working, you need to do a backflush on it. A backflush is when water is forced through the heat exchanger and into the furnace. This cleans out any debris that may be blocking the heat exchanger and allows the furnace to operate at its full potential. Here are four steps on how to do a backflush on a heater core:

1) Shut off all power to the furnace.

2) Open the door to the furnace and remove any obstructions in the flow of air. You can use an extendable pole or a long piece of hose to help clear the way.

3) Turn on all power to the heater core and open the water valve on the side of the tank. The water should start flowing quickly and continue until there’s no more pressure coming from the source (the water valve).

4) Close off both valves and turn off power to the heater core.

Why You Should Backflush A Heater Core

Backflush a heater core if it’s causing an engine coolant leak. The procedure is simple and can be done in just a few minutes. Here’s what you need:

1. Raise or open the hood of your car.

2. Find the thermostat housing on the engine block (look for 3 hoses coming out from it).

3. Loosen the three bolts that hold the housing to the engine block (they are usually about 1 inch long and about 1/4 inch diameter).

4. Carefully pull the housing off of the engine block. You may have to wiggle it around a bit to get it started moving because it’s sealed with thermal paste. If so, use a rag or piece of paper to wiping off any excess paste before re-installation.

5. Once the housing is off, you’ll see several electrical wires connected to it (these are usually red and black). Disconnect all these wires using an adjustable wrench, being careful not to short anything together while they’re still attached to their connectors on the housing

6. To backflush the heater core, pour about 2 gallons of boiling water into the tank below where the heater core is located (you may have to remove some insulation from around this area first). Immediately start up your car and let it run until all of the hot water has been forced out of the heater core (it should take only a


If you’re like many homeowners, you’ve probably had to deal with a heater core that’s not heating up as it should. In this article, we’ll show you how to backflush a heater core and solve the problem. By following these simple steps, you should be able to get your heater working properly again in no time. Thanks for reading!