What is an EGR Valve? Everything You Need To Know

Have you ever heard someone say “EGR valve” but you’re unsure what it is?

In this article, you’re going to learn:

• What is an EGR valve?
• How does an EGR valve work?
• How to clean an EGR valve
• EGR valve replacement costs

What is an EGR valve?

In most internal combustion engines (ICE), Exhaust Gas Recirculation (EGR) is a method used to control Nitrogen Oxides (NOx) emissions, produced as the end product during the running of the combustion engine.

Air from the environment, mostly a combination of Oxygen and Nitrogen, combines with the fuel that ignites inside the combustion chamber ending with NOx emissions being produced.

The EGR system works by returning a small portion of exhaust gas to the engine’s combustion chambers through the intake manifold, lowering combustion temperatures and therefore reducing the amount of NOx emitted.

The EGR valve is a component that controls the flow of exhaust gas back into the engine to reduce emissions. It is usually closed but opens when the engine load increases.

How does an EGR valve work?

Most modern cars incorporate an EGR valve into the engine design to reduce NOx emissions which helps the manufacturer to meet stringent emissions regulations.

EGR systems recycle a portion of the exhaust gas back into the combustion chamber, which after combining with fresh air intake helps lower the amount of Oxygen and increase the water vapour content. The addition of water vapour content to the combustion mixture helps reduce the peak combustion temperature.

The EGR valve begins working once the engine has been started, is at the correct temperature and the vehicle’s speed increases. Gradually, the EGR valve will regulate the flow of exhaust gases.

Once the car slows down and the engine stops, the EGR valve will return to its closed position to prevent the flow of exhaust gases.

How to clean an EGR valve

Cleaning an EGR valve at home isn’t recommended unless you’re a professional mechanic and you have the right tools for the job. It’s much easier and safer to consult a professional such as your local car mechanic or dealership.

But if you were to attempt the cleaning of an EGR valve yourself, you might need tools such as:

• Socket wrench
• Ratchet
• Extension bar
• EGR valve cleaner or carburettor cleaner
• Brushes (soft and stiff)
• Rags or paper towers
• Work gloves

And the general cleaning process might look something like this (model-specific):

1. Disconnect battery: To prevent accidental activation, disconnect the negative battery terminal.
2. Locate and remove the EGR valve: Refer to your vehicle's manual for the exact location. Use the socket wrench and ratchet to loosen and remove the bolts holding the EGR valve in place.
3. Inspect for damage: Check the valve for visible carbon buildup, cracks, or damage. If severely damaged, it may need replacement.
4. Clean the valve:
   1. Spray cleaner: Spray the cleaner into the valve's passages and onto the carbon buildup. Let it soak for a few minutes.
   2. Scrubbing: Use a soft brush to scrub away the loosened carbon. For stubborn deposits, a stiffer brush might be needed.
   3. Rinse: Use a spray of cleaner or carburettor cleaner to rinse away any remaining residue.
5. Clean the intake manifold: Carbon buildup can also accumulate in the intake manifold. If it's accessible, clean it using the same methods as the EGR valve.
6. Inspect gaskets: Check the gaskets for wear or damage. Replace them if necessary.
7. Reassemble: Carefully reattach the EGR valve, ensuring a tight seal. Replace the gaskets if needed.
8. Reconnect battery: Reconnect the negative battery terminal.
9. Test for leaks: Start the engine and check for any vacuum leaks around the EGR valve or intake manifold. If you hear hissing sounds, there might be a leak. Tighten any loose connections.

As stated above, a job like this isn’t for an amateur if you haven’t got the tools or experience and a professional mechanic/car dealership would be the safer option.

EGR valve replacement costs

There isn’t a clear answer for this as it depends on the make and model of your car. Usually, the labour costs will be higher than the actual costs of the EGR valve itself and all comes down to how complex of a job it is on your car.

If you need a quote for an EGR valve, you can contact your local Chorley Group dealership today and we’ll be happy to assist.