5 Symptoms of a Clogged EGR Cooler and Replacement Cost

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clogged egr cooler

If you’re a car owner, there’s a good chance you’ve heard of the Exhaust Gas Recirculation (EGR) cooler. It’s responsible for cooling exhaust gases before reintroducing them into the engine. However, like any component, the cooler could fail, bringing other critical parts down with it. It could also involve your turbo.

Typically, the issue begins with the cooler failure. Understanding when and how to spot EGR cooler problems and how they might affect your turbo is critical for minimizing possible damage, problems, and costly repairs.

Think your car isn’t trying to tell you something? It might not be speaking in words, but it could be sending you signals that something is wrong. In this article, we’ll discuss the EGR cooler failure symptoms so you can know what to look for if yours needs replacing.

Bad EGR Cooler Signs and Symptoms

  • Coolant Loss
  • White Smoke
  • Overheating Engine
  • Exhaust Leak
  • Check Engine Light

What Is The EGR Cooler?

While the EGR system is critical for emissions reduction, it can also adjust the internal engine air heat. This keeps your engine from overheating, making it essential to maintain. The Cooler problem manifests itself in strange-looking emissions and engine overheating.

EGR coolers are a standard component in almost every modern automobile but are particularly prevalent in diesel engines. Since diesel fuel produces more harmful emissions than gasoline, the EGR system is especially vital for a diesel engine.

Dysfunction of your cooler might jeopardize your car’s reliability, resulting in severe engine damage and potential degradation of many other components. It can frequently go undiagnosed for an extended period since the symptoms aren’t always visible.

EGR Cooler Functions

Pollutants aren’t limited to the unburned gases emitted by your engine. They arise when the intense heat generated within your diesel engine’s combustion chamber breaks the chemical bonds, forming newer molecules. When this heat mixes oxygen and nitrogen atoms in the air, ozone (O3) and nitrous oxide (NOx) emissions are generated.

NOx can contribute to smog, and when combined with water, it could result in acid rain. While our ozone layer assists defend humans from ultraviolet radiation, this gas may create respiratory issues at ground level, particularly for asthmatic individuals.

After cooling the combustion temperatures, the engine’s intake system recirculates the exhaust gases. This contributes to lower emissions and less heat load on exhaust valves and cylinder head gaskets, extending the component’s lifespan. While not all cars feature EGR coolers, those who do are critical for maintaining driving efficiency.

By reducing the air and fuel mixture through a tiny quantity of inert exhaust gas, Exhaust Gas Recirculation (EGR) decreases combustion heat. This has a minimal influence on car efficiency while significantly lowering the likelihood of chemical processes that result in pollution.

On the other hand, reducing the mixture is substantially more efficient when the exhaust is cold, not heated. That is when the cooler enters the scene. The cooler is routed between the turbocharger and the exhaust gas recirculation (EGR) valve. Its structure contains a hollow tube or set of tubes through which the heated exhaust fumes pass. Multiple engine coolant channels flank these tubes.

Heat is conducted via the sidewalls dividing the coolant and exhaust, resulting in the delivery of cooler and cleaner exhaust gases capable of lowering the maximum combustion temperature. The car’s computers regulate the EGR cooler’s stream of exhaust gases through the EGR valve.

All the heat generated by your exhaust system is merely transmitted to your car’s cooling system. This excess heat is quickly absorbed via your radiator. But, since its cooler links your car engine’s exhaust and cooling system, problems within the cooler may result in coolant loss, engine overheat, and other engine damage.

Bad EGR Cooler Signs And Symptoms

Maintaining EGR coolers isn’t that difficult if you’re aware of when it requires care. Some indicators can be noted that can assist you in repairing or replacing coolers. Now, let’s review the indications that could indicate if your cooler is damaged and needs to be replaced.

Coolant Loss

Most of your coolant evaporates within the failing cooler, and being blasted out via the exhaust would eventually result in a low coolant level. While coolant loss isn’t usually indicative of a failing cooler; however, it’s a reasonably safe assumption if coupled with white smoke. Whenever you notice you don’t have enough coolant and see no apparent coolant leak, this is a solid indication that you have cooler issues; adding coolant will not resolve the problem!

White Smoke

This could be challenging to observe independently; thus, it’s a bright idea to seek assistance from a companion or a buddy. White smoke might indicate that your cooler had already leaked inside and contaminated your EGR system with coolant. The coolant passing through is heated and released as gas—and isn’t acceptable in the long run. While this won’t directly affect your exhaust system, the decreasing coolant level could result in engine overheating.

Exhaust Leak

Another symptom of failing coolers is exhaust leaks. Whenever the gaskets on your cooler degrade or the cooler are compromised in any way, an exhaust leak might emerge. Any exhaust leak can be identified by a noticeable tapping or hissing noise emanating from your car’s front. This reduces the effectiveness of EGR systems and has a detrimental effect on engine performance.

Overheating Engine

Overheating is one of the first signs of a probable cooler failure. If there are faults with your cooler that hinder the passage of exhaust gases thru the cooler, this might result in overheating. Carbon might accumulate on the interior of your cooler throughout time, restricting flow through the cooler. A failing EGR cooler could lead your engine to overheat since it’s unable to cool down the exhaust gases effectively. If left untreated, engine overheating may result in engine knock, as well as significant damage.

Check Engine Light

Usually, your car’s electronic control unit (ECU) would detect a disparity in the systems and activate its check engine light. This might illuminate if the cooler gets congested or the EGR system isn’t operating correctly. In any case, whenever your check engine light illuminates, it’s time to inspect your engine.

EGR Cooler Failure Causes

An EGR cooler malfunction for a variety of causes; however, what if the EGR cooler fails? While some are repairable, usually, a failing EGR cooler requires replacement. Below are among the possible causes for your EGR Cooler to fail.


Occasionally, the cooler’s channels get clogged, preventing efficient conditioning of exhaust fumes. This is difficult to determine without dismantling and inspecting the cooler, but sometimes overheating or higher fuel usage might suggest this is the case.


Specific coolers could be corrosive, depending on the usage. This might be caused by wear, particle buildup, or acidic precipitation at cold temperatures.

Thermal Stress

Due to the frequent cycling of severe temperatures, the cooler is exposed to exhaust fumes that reach up to 800°C and then cool to roughly 200°C. It could inflict damage to your cooler throughout time, resulting in leaks or total failure.

How To Clean The EGR Cooler

Replacing your cooler may be costly. Although failure is almost always unavoidable, you could prolong its life by maintaining this component clean. Cleaning soot and dirt from the cooler might help reestablish an equal coolant flow that can help lower internal pressures and increase cooling efficiency. There are a few ways to clean coolers; however, they all follow the same approach.

  1. Ensure that the cooler is removed from your car.
  2. Add detergent to the cooler.
  3. Immerse the cooler in water for a few minutes to dissolve residues and buildups.
  4. Wash the cooler well to eliminate any loose particles.
  5. Allow the cooler to dry completely before reinstalling it to the car.

Many repair shops use an ultrasonic cleaner to clean EGR coolers, particularly filthy passageways. When running detergent thru the passageways, these ultrasonic waves shake the carbon loss. This may significantly expedite the cleaning procedure.

EGR Cooler Replacement Cost

So you’re in the search for a brand new EGR cooler but aren’t sure where to begin? Consider the cost-influencing aspects. Numerous factors influence replacement prices, along with the item itself, labor, area, availability, and car make and model.

Depending on the application, a new EGR cooler will cost around $270 up to $3700. The upper end of the spectrum is often reserved for customized or high-performing engines; therefore, you’re likely to be dealing at the lower end of the scale for a regular vehicle.

Labor costs are dependent on the kind of car you own. Engine bays are all designed differently, and the ease with which your EGR cooler can be accessed affects the labor cost. Also, your location affects most items’ prices, mainly if components aren’t widely accessible in your area. It’s advisable to inquire at your local shop for further information on what to anticipate.


So, if you’re undergoing any of the signs and symptoms listed above and you suspect the EGR cooler is to blame, it might be time for a new cooler. Of course, there are other aspects to weigh when selecting a new cooler, such as price and customer reviews – but hopefully, this post has helped you narrow down your options. And always remember, drive safe!


What causes EGR cooler to clog?

Of course, the most typical reason is inadequate coolant flow. This often occurs due to a clog or contamination in the cooler. This limitation of coolant allows the cooler to fail to work correctly due to the increased temperature, which often tosses the sensor off.

What happens if my EGR cooler fails?

The car’s computer regulates your EGR cooler’s circulation of exhaust gases through its EGR valve. But, since your cooler links your engine’s exhaust and cooling processes, malfunctions within the cooler may result in coolant loss, overheat, and engine failure, plus other problems.

Can EGR cooler be cleaned?

EGR coolers are similar to radiators, although they utilize water to cool heated exhaust gases rather than air to cool the heated water. This means they can be maintained in the same way as a radiator.

How do I know if my EGR cooler is leaking?

White steam or smoke might signify that your EGR cooler leaks inside, allowing coolant to enter your EGR system. While this won’t directly affect your exhaust systems, the decreasing coolant volume will lead your engine to overheat.

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