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Can You Bypass Heater Core? (Side Effects & More)

The heater core is used in the cabin of the car as a heating system. The heater core is an essential internal part of a car. It helps the car engine to release heat into the cabin. Today, we are going to discuss whether one can bypass the heater core.

Can you bypass the heater core?

One can bypass the heater core as a short-term solution. But in the long run, bypassing the heater is not recommended. Because bypassing the heater takes away the heating and windshield defogger features of the car. It is better to repair or replace the heater core instead of bypassing it.

Bypassing the heater core has drastic side effects. One of them is that the car will lose its heating system and will no longer be able to heat the cabin of the car. That is a major setback if you are leaving in a cold country. 

The best step to take here would be to repair or replace the heater core.

Many people bypass the heater core instead of replacing or repairing it as a cost-effective measure. But in reality, it increases the maintenance cost of your car. Because bypassing the heater core will decrease the chance of repairing it. 

It will increase the cost because an old heater core will a new one is more expensive than repairing it.

Is it bad to bypass the heater core?

Sometimes the heater core of the car stops working and the coolant starts dripping down into the cabin of the car. In that case, the heater core must be repaired. But to avoid the repair cost, some people decide to bypass the heater core as it is a cost-effective thing to do.

But bypassing the heater core without the help of a professional is not recommended. It can mess with the heating system of your car. It can also cause problems to the windshield defogger system.

Basically, you are giving up the heating privilege of your car by bypassing the heater core. You are also giving up additional safety measures by compromising on the windshield defogger system. 

So all things considered, bypassing the heater core can be a bad thing for the condition of your car.

Why would someone bypass the heater core?

There are several reasons that can compel you to bypass the heater core of your car. They are:

Leakage of coolant:

The heater core is basically used to divert the hot coolant into the cabin of the car. When the heater core becomes faulty, it starts leaking coolant into the cabin of the car instead of maintaining the heating system. That is when the need to bypass the heater core arrives.

Unclear windshield:

The windshield also gets affected when your heater core stops working perfectly, the unfiltered coolant starts leaking onto the windshield. That increases the safety risk of your car. To get rid of this risk, one might feel the need to bypass the heater core.

Overheated car engine:

The faulty heater core leaks coolant into the cabin and the windshield. The work of the coolant is to keep the heat of the engine at a moderate level. If the coolant starts leaking into the cabin and the windshield, there would not be enough coolant left in the cooling system of the car.

The heater core also helps the cooling system to work properly. Without enough pressure from the heater core, the cooling system will fail to perform its functions perfectly. This will naturally cause the engine of the car to overheat. 

To prevent the car engine from overheating, one might feel the need to bypass the heater core.

Will I still have heat if I bypass the heater core? Will bypassing the heater core cause overheating?

The main purpose of the heater core is to maintain the flow of hot coolant into the cabin of the car. If your heater core stops working and starts leaking coolant into the cabin of the car, then you will have to bypass the heater core to stop the leakage. 

By doing so, you will lose the heating privilege of the cabin. The heater will stop heating the cabin of the car.

The cabin of the car will be under heated if you bypass the heater core. So bypassing the heater core will not be overheating the cabin of the car. But it can certainly overheat the engine of the car. The cooling system of the car works better when the heater core is functioning properly.

If you have a faulty heater core and you bypass it, then the heater core will stop working and the cooling system will also lose its effectiveness. The engine of the war will overheat as a result.

Side effects of bypassing heater core:

There are quite a few side effects that appear after you bypass the heater core. They are:

Lack of heat:

The main purpose of the heater core is to provide heat into the cabin of your car. If you bypass the heater core, the heater core will fail to send an adequate amount of heat into the cabin of your car. Thus in the winter, you will start freezing in the car due to lack of heat. 

So it is better to repair the heater core instead of bypassing it if you leave it in cold condition.

Threat to windshield defogger:

Bypassing the heater core can pose threat to the windshield defogger system of your car. The heater core prevents the windshield from fogging up in the cold climate. Driving your car with a faulty windshield defogger can cause accidents. 

The wise thing one can do in this situation is to repair the heater core. Because bypassing it would pose unavoidable threats.

Development of corrosion and rust:

Bypassing the heater core and leaving it idle can cause the heater core to develop corrosion and rust. The cost of repairing a heater core is much less than the cost of replacing it. So if you bypass the heater core and let it rust away, you would not be able to repair it. 

Repairing the heater core would be the best cost-effective move here.

How to bypass the heater core?

There are several steps involved when it comes to bypassing the heater core. They are:

Removal of the heater hoses:

Let’s say the car is a Jeep Cherokee containing a Chevy 350 engine. In order to bypass the heater core of this sort of car engine, first of all, you will need to remove the heater hoses from the connecting points. 

These two hoses are used to carry coolants into the engine of the car and into the cabin of the car. The heater core is connected to the engine mechanism. It is also connected to the cooling system through the hoses.

Removing the heater hoses will require a screwdriver because of the clamps of the hoses. If the heater core hoses do not contain clamps, then the hoses will have to be cut out.

Join the hoses:

Next, you will have to join the hoses together with help of a plastic tube. The diameter of the plastic tube has to be the same as the diameter of the heater hoses. After that, you will be required to tighten the clamps of the heater core hoses. 

Joining the hoses together with the help of the plastic tube will successfully bypass the heater core and it will not affect the cooling system.

Extra precaution:

The engine of the car needs to be shut down for a while before you start bypassing the heater core. After you have finished the process of bypassing the heater core, turn on the engine of the car to check if the bypass has been successful. 

If your heater core still leaks coolant into the cabin of the car, it is better to replace or repair it at the auto repair shop.

Will my AC work if I bypass the heater core?

The AC system of the car does not suffer if someone bypasses the heater core. The AC system is protected from the side effects of bypassing the heater core. So your AC will work fine even if you bypass the heater core as it is protected with the valve.

Bypassing the heater core will only have side effects on the heating of the cabin and the windshield defogger. The AC system will not be affected by the absence of a fully functional heater core. 

But it is better to repair or replace the heater core to avoid long-term complications.

Final thoughts

The heater core of the car’s cooling system can be bypassed easily and effectively. When coolant starts leaking into the cabin of the car, the heater core is usually bypassed. But it is not a wise move because of the side effects. Bypassing the heater core can cause the car engine to overheat.