Why Should You Clean The EGR Valve of a Car?

Learn the benefits of cleaning your EGR valve and how it can improve your car's performance. MyCar.Repair UK experts provide valuable tips.

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Do you want to know about EGR cleaners and their purpose? Are you looking for the best EGR cleaner available in the market? If yes, then this article is for you because we have got you covered with all the necessary information about EGR cleaners!

EGR valve covered in dirt and soot deposits

What is EGR cleaning?

EGR stands for exhaust gas recirculation. An EGR valve is present in the modern internal combustion chamber of the car engine. It is an important emission control device that connects the exhaust manifold to the intake manifold.

Exhaust gas recirculation controls the number of nitrogen oxides (NOx) emissions that occur as byproducts of the combustion process.

How do EGR systems work?

The combination of nitrogen and oxygen which comes from the air gets mixed with the fuel. This process gets ignited in the combustion chamber and hence increases its temperature. In this way, the formation of nitrogen oxide occurs, which is extremely harmful to the environment and living beings.

Here, the EGR system plays its role. It returns several exhaust emissions into the chamber through the intake manifold. Resultantly, it lowers the temperature of the internal combustion chamber of the engine. In this way, it helps reduce emissions of NOx. The EGR valve, being a vital component of the EGR system, plays an important role in this procedure.

EGR valve

EGR valve disassembled and ready for cleaning

As mentioned earlier, this vital part of the EGR system joins the exhaust manifold to the intake valves. An EGR valve is usually closed and is operated either by a vacuum or by a stepper motor. The function of an EGR valve is to recirculate the gas emissions to control them.

This valve starts working when the engine gets turned ON and reaches its optimal operating temperature. Moreover, when the car gains enough speed, this EGR valve gets activated and then gradually controls the emissions.

However, when the car engine stops or decelerates, the EGR valve returns to its closed state. In this way, it stops the exhaust gases from flowing through the system.

Reasons for damaged EGR valves

There are several reasons for the damage that happens to the EGR valve. Some of these reasons are listed as follows:

  • The EGR valves are continuously subjected to wear and tear, so they become damaged with time. Moreover, they do operate in extreme conditions which speed up their deterioration process.

  • A hindered or restricted EGR pipe may also cause damage to the valve. This pipe is a part of the air intake manifold. It is used for returning exhaust gases to the engine. Those exhaust emissions are mostly contaminated with sludge and soot. These soot emissions grow thicker and clog the pipelines with time, which causes damage.

  • A faulty temperature sensor or airflow sensor can also lead to damage to the EGR valve. Carbon build-ups on the temperature sensor might make it faulty. As stated earlier, this valve gets opened and closed. The temperature sensor provides this information to the valve. If the sensor itself is faulty, it will fail to provide the necessary information to the valve. Hence, it may damage the EGR valve.

  • A sticky EGR valve can also cause damage. The same pollutants that clog the EGR pipe also contaminate the valve. Consequently, the valve may become stuck in a closed, opened, partially closed, or partially-opened state.

    When the valve is stuck in a closed state, it will not allow any exhaust gas recirculation throughout the engine. Ultimately, the engine temperature will rise, and it may lead to knocking noises coming out from the engine.

    On the other hand, if the valve becomes stuck in an open position, it will allow excessive emission of the exhaust gasses into the car engine. These additional exhausts will cause extra rough idling to the vehicle.

  • Vacuum supply problems for vacuum-operated valves and electrical issues for motor-operated valves can also cause damage to the EGR valves.

  • Faulty or missing EGR gaskets, restricted catalytic convertors, intake leaks, dirty air filters, damaged switching valves, improper vacuum hose connections, damaged turbochargers, and faulty diesel particulate filters are also some of the common reasons for damaged EGR valves.

Symptoms of a faulty EGR valve

Following are some common symptoms and signs of a faulty EGR valve:

  • Rough idling: When the valve remains open and more than usual exhaust gas recirculation occurs, it leads the vehicle to idle roughly. The vehicle may even stall out if it happens for more time.

  • Illuminated check engine light: If the check engine light gets turned ON, it might be indicating that your EGR valve has become faulty.

  • Shaking engine: If the engine starts vibrating more than usual, check your EGR valve because it might be damaged.

  • Vehicle Inefficiency: If you notice a decrement in the mileage of your vehicle or the car started to consume more than usual fuel, the EGR valve might be bad.

  • Burnt smell: The burning smell of fumes or gases may also indicate a bad valve.

  • Poor acceleration: If you face difficulty in starting the car or poor acceleration while driving, it could indicate a damaged EGR valve.

  • Tapping noise: When the internal combustion chamber of the engine becomes overheated due to clogged passages, it leads to knocking or tapping noises. These noises sometimes indicate a faulty EGR valve.

  • Increased emissions: When there is an increase in the emissions of nitrogen oxides, the engine starts to perform erratically. These increased emissions might indicate a bad EGR valve.

Frequency for EGR cleaning

Most car manufacturers recommend cleaning the EGR valve using an EGR cleaner every 50,000 miles drive of your vehicle. This cleaning is necessary for controlling emissions as well as for maintaining engine performance and fuel economy.

You do not have to take your vehicle to car experts or mechanics for EGR cleaning. You can do it by yourself just by following the step-by-step procedure and having some common tools.

How to find out the EGR valve in your vehicle?

Locating the EGR valve can vary from vehicle to vehicle. Usually, it is present on the backside of the car engine. However, here are some signs that will help you locate the valve effortlessly:

  • In older car models, this valve is usually round. It is a thick semi-flat disc made of metal having a diameter of about two to three inches. A slender hose for vacuum is connected on the top of this disc.

  • In modern car models, the valve is similar along with a small sensor in the shape of a box. In addition to that, an electrical saddle is also attached to this valve.

  • Other models also use a block-shaped or cylindrical valve with sensors and an electrical harness attached to them.

In case you still do not find out your EGR valve, you can search its location online by inserting your car make and model into any auto parts online service. It will show you a picture by which you can easily identify the component.

Apart from this, you can also go through your car manual to find out what your car’s EGR valve looks like. This manual will also tell you the exact location of the required component. In this way, you can locate the valve with so much ease and save a lot of time.

Things required for EGR cleaning

The following things are necessary to clean out the EGR valve:

  • EGR cleaner

  • Socket set

  • A dull scraper

  • Ratchet along with its extension

  • Wire brush for pipe cleaning

  • A clean rag

  • Goggles for safety

  • Acid-proof gloves for safety

  • Repair manual (completely optional)

  • Extra EGR valve kit (if required)

  • Adaptable wrench (if required)

How to remove the EGR valve?

After finding out the EGR valve, the next step is to remove it so that it may get cleaned later. Removing the EGR valve requires the following steps:

  • First of all, check out the slender vacuum hose attached to the valve. Remove it carefully from the valve to proceed further. If the hose appears faulty or broken to you, get it changed right now. A bad vacuum hose might lead to EGR failure and poor functioning of the exhaust system.

  • The hose you just removed will be attached to another component from the other end. Check out other attached hoses to that component to ensure that each of them is in good condition.

  • After that, remove all the electrical connectors and wires from the valve.

  • Now take out the ratchet, ratchet extension, and the socket set to remove all the bolts from the valve. There are usually two to four bolts that you have to unscrew.

  • There might be a pipe attached to the valve as well, coming from the exhaust manifold. At that manifold, remove the pipe using an adjustable wrench or any wrench you have.

  • Now, completely remove the EGR valve. After its removal, check for the EGR gaskets. If they look fine to you, leave them as they are. On the other hand, if you see any kind of fault in them, replace them immediately. You can also purchase gasket paper to repair that!

How to do EGR cleaning?

For safety purposes, put on the goggles and acid-proof gloves to avoid any mishap. Now, we have to carefully clean up the carbon and soot deposits from each portion of the valve. Also, do not forget to wash out the attached ports and pipes thoroughly. Follow these easy steps for EGR cleaning:

  • Spray directly the EGR cleaner onto the valve to remove any carbon buildups. Evenly spray out all the inlet valves and the exhaust valves using the strong power jet spray cleaner.

  • Wipe off the spray from the sensitive plastic parts and the electrical components immediately as a preventative measure. This is done to ensure that no damage happens to the sensitive components.

  • Now take out the pipe cleaning wire brush along with the scraper to remove any carbon buildups from the valve.

  • After that, take out a soft-bristled brush to completely remove the waste materials and wipe them off with a clean rag. Do not put so much pressure on the sealing surfaces, otherwise, the gases trapped inside might get leaked.

  • If the deposits are too hard, leave the EGR valve cleaner for a few minutes until they get completely dissolved. But, do not leave this on sensitive components, such as electrical ones, or you will damage the valve.

  • For rock-hard deposits, some people leave the cleaner overnight, but we recommend not doing it to be on the safer side.

  • Always check for the intake manifold. Remove all the deposits inside this manifold using the cleaner. Do not forget to carefully follow the directions written on the packaging. If you are not willing to do it by yourself, you can also invest in getting a carb cleaner service.

  • After you have finished cleaning all the components and pipes, reconnect all the removed parts.

  • Do not forget the gasket, and make sure all the parts are connected right in their place.

  • Take out your vehicle for a ten-minute test drive with two to three truculent accelerations. Now, the symptoms of a bad EGR valve must disappear.

The best EGR Valve Cleaners

There are several good options for EGR valve cleaners available in the market that show excellent results. We have listed our top brands for the best EGR valve cleaners in the market:

Liqui Moly Pro-Line

Liqui Moly Pro-line intake system purge is hands down the best EGR valve cleaner. It not only efficiently removes the deposits and soot but also increases fuel efficiency by decreasing fuel consumption.

In addition to that, it promises functional performance and fuel economy both in petrol and diesel engines. Hence, it enhances the reliability and worthiness of diesel engines.

Ways to use

  • If the EGR valve of your vehicle is extremely dirty, you can remove it by following the above-mentioned instructions. After that, you can thoroughly clean the valve using this EGR valve cleaner.

  • Another simple method states that just spray the EGR valve cleaner via the air intake system in intervals. It is efficient enough if you follow this method at least once a year when changing the oil. Moreover, this method saves time for car mechanics.

Therefore, if you are looking for some affordable as well as super-efficient EGR valve cleaner, go buy this Liqui Moly formula right now!

Increase the life of your engine by an immediate thorough cleaning using Liqui Moly Pro-Line intake system purge. Click here to buy now!

For Petrol engines:


For Diesel engines:


Wynn’s Diesel EGR Extreme Cleaner

This product is specifically designed to clean diesel engines thoroughly. Wynn’s Diesel EGR extreme cleaner has a lot of promising properties. It is a strong power jet spray cleaner for cleaning out the contaminations and deposits inside the air intake system.

This cleaner has a huge name in the automotive industry to support cleaning action. It wonderfully dissolves gum, tar, lacquer, soot, and carbon deposits. Moreover, it offers a regular and stable idle and solves all the starting issues. In addition to that, it restores perfect airflow in the combustion engines.

So, try getting your hands on this amazing product!

STP Diesel EGR Spray Cleaner

This product has similar properties to that of Wynn’s diesel EGR extreme cleaner. It offers great value for money as well as outstanding car performance and fuel economy.

It is an easy-to-use product that helps in reducing emissions to a huge extent. It efficiently dissolves gum, lacquer, deposits, tar, carbon buildups, etc. Also, the engine runs stable. Moreover, it is compatible with the fuel system, modern diesel vehicles, fuel tank, exhaust gas recirculation system, airflow sensors, turbo systems, etc.

So, we recommend you consider this budget-friendly option!


For how long can an EGR valve last?

With proper maintenance and care, EGR valves can last for up to 10 years.

Can we clean the EGR valve without removing it?

Yes, you can clean an EGR valve without removing it.

Can we use WD40 for EGR cleaning?

We do not recommend using WD40 for EGR cleaning. Invest in a good EGR valve cleaner (like Liqui Moly cleaning spray) to get the best results.

Does removing EGR increase engine power?

Yes, it does.

How long does it take for the EGR cleaner to work?

Usually, it takes around 40 minutes to an hour for an EGR valve cleaner to work properly.

Can I use a carb cleaner for EGR cleaning?

Yes, carb cleaners work the same just like the EGR valve cleaners.

What causes carbon buildups?

When the oil meets the harmful nitrogen oxide gases and passes through the engine, it leads to carbon buildup.

Final Word

In a nutshell, EGR cleaning is necessary for the smooth running and exceptional performance of the engine. You do not have to wait for the symptoms to occur for the bad EGR valve. Get the EGR cleaning done at least once a year using the best Liqui Moly EGR valve cleaner!

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