EGR Cooler – What is That? What are the Common Problems?

In internal combustion engine systems, there are different kinds of systems to make different kinds of duties. One of these systems is the EGR cooler. Here you can find detailed information about the EGR cooler applications. And also you will learn about the general problems that you face with these applications. Solutions and replacement costs are the additional information about them.

What is EGR Cooler?

EGR Cooler
Image Source: Shutterstock.

EGR cooler is a system that we find in the EGR system. The meaning of EGR is Exhaust Gas Recirculation. In modern engines, the exhaust gases produced by internal combustion engines are not directly expelled from the exhaust. They contain a very good amount of heat. And also in diesel engines, the exhaust gases are converted into very bad pollutants such as O3 and NOx.

So, the main duty of the EGR system is to recirculate the exhaust gases to decrease the pollutants. The pollutants are increased in diesel engines because of the very high temperature and pressure. To decrease the temperature and pressure, the exhaust gases are directed to the EGR systems through the EGR valve. The ECU system of the engine opens the EGR valve and takes the hot and high-pressure exhaust gases.

These exhaust gases go through the EGR cooler. EGR cooler is a very basic system that has cooling channels. Once the exhaust gases pass through the EGR system, the temperature of the gases decreases. And these EGR coolers are working with the coolant of the engine. The coolant received the heat from the engine and decreases the total temperature of the gases. And this reduces the total pollutant gases.

Why does EGR Cooler System Fail?

There can be different kinds of reasons why the EGR cooler system fails in general.

  • The first and most common reason is the corrosion during the time. Because the EGR cooler application is a system that exposes very high temperatures and pressures regularly. The flow of this corrosive fluid through the cooler makes them weak and problematic. And after a while, leaks can start and the EGR system provides problems.
  • Also, very high temperatures can cause cracks or warps on the EGR cooler. The exhaust gases of a typical diesel engine can be high as 800 degrees Celsius. And once the exhaust gases pass through the EGR cooler, they decrease to 200 degrees Celsius. This heat takes can cause some problems.
  • Also, there can be blockages because of the carbon built up by the exhaust gases. This will reduce the effectiveness of the system and also this will increase the performance loss of the engine.

What are the Symptoms of a Bad EGR Cooler?

There are different kinds of symptoms that you will see with the EGR coolers. And if you have these symptoms you need to deal with the problem.

  • The first and the most important symptom of a bad EGR cooler is the smoke. The common reason for the smoke is, if the EGR system does not work properly, the bad gases will not be reduced. And when NOx connects with water or moisture, it will create smoke. Also, another cause is, if the EGR cooler leaks fluid into the exhaust, you will see smoke coming from your exhaust.
  • If the EGR cooler system leaks fluid to the exhaust gases going through the EGR system, you will see a decrease in the coolant of your engine. And you will not see any leaks. Because all the coolant goes through the exhaust system.
  • Overheating on the turbo is another important symptom that you will see. And overheating for long periods can cause much worse problems.
  • If you have a problem with this part of your car, the check engine light will be on your dashboard.

Lots of People Deleting the EGR System

The primary duty of the EGR system is to reduce the harmful emissions from your car. And people are mostly thinking about deleting the EGR system from their engines. And also, because of the extra barrier that the exhaust gases must flow, this resistance reduces the engine HP slightly. Because of this, lots of people are deleting the catalytic converters and EGR systems from their cars. Because the environmental hazard is not a problem for them.

But we do not recommend you do it. If you delete these systems, the emissions that your car makes will be very harmful to the environment. And also, in regular car check-ups, you will not able to pass the emission tests. And if they will find out that you are driving your car without these systems, you can face very big penalties.

So, do not delete the EGR system if you are considerate about environmental use, and do not take the risks that we explained above.

How Much Cost the EGR Cooler Replacement?

It is very hard to give a definite answer to this question. Because different kinds of parameters affect the general prices. The first parameter is the model and year of the vehicle. And the other one is if you choose aftermarket or OEM parts.

So, if we need to give general prices for these parts, the EGR cooler generally costs somewhere between $50-$150 according to your vehicle. And also, the labor costs will be around $100 which makes you a general $250-$300 of total costs in general.

Can You Run a Car without an EGR Cooler?

If the EGR cooler breaks down, your EGR valve will continue to operate. And this means the exhaust gases will go through it. You can drive your car for low distances. But you need to drive it directly to the service of your car. And you need to fix the problem of your EGR system immediately.

But if you delete the EGR cooler, they generally delete the EGR valve. And exhaust gases are directly directed to the turbo. And if this turbo and the other components of the engine that exposes to high temperatures of exhaust gases can not withstand these high temperatures, these parts will fail eventually. So, you need to replace these parts with systems that are higher temperature tolerances.

Can You Clean the EGR Cooler?

Also if the problem is the carbon buildup in the system, you can easily clean the EGR cooler system without any problem. You just need to consider these tips if you want to clean these parts.

  • First of all, you need to remove it from your vehicle. It is not an easy thing. You need to remove the coolant connections and the turbo and valve connections after placing the EGR cooler.
  • Once you remove this part, you need to fill it with a detergent. And let the cooler stay in the detergent for a while to lose the carbon deposits.
  • After that, you need to rinse the cooler thoroughly and reinstall it.


These are all the general considerations about the EGR cooler parts that your diesel engine has. If you have additional questions and comments about the EGR cooler systems, you can leave them below.

Check the other contents about car maintenance and car parts;

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Uğur Uygun

Hello everyone, I am Uğur. I am a mechanical engineer who has experience in different R&D departments of HVAC companies. With my best friend, I decided to build this website to share out knowledge and experience. And also, I am interested in automotive. So, I am writing about automotive and automotive-related articles here. Sharing my knowledge and experiences on these topics is a very big pleasure for me. I am willing to answer all of the questions people have about these topics.

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