What Is an EGR Valve? - Enji


What Is an EGR Valve?

May 16, 2022

What Is an EGR Valve?

To the typical car owner, everything under the car’s bonnet is likely a bit of a mystery. How often has something gone wrong and you’re left thinking ‘Where do I start?’ 

The EGR valve is a lesser-known component of a car’s machinery, but it plays an important part in the function of the car! This small part can cause some tricky issues if left unnoticed, so read on to learn more about the EGR valve. 

What Is an EGR Valve?

An Exhaust Gas Recirculation Valve, also known as an EGR valve, is a component of a vehicle’s machinery that recirculates exhaust gas to the engine’s intake system. The EGR valve helps maintain positive engine health, contributing to a well-functioning exhaust system. 

The primary function of an EGR valve is to act as an emissions control device, in order to reduce the overall emissions being produced by the car. Because cars produce an excessive amount of emissions, the EGR valve helps reduce unnecessary additions to the atmosphere. 

Overall, the EGR valve increases the efficiency of the engine, reduces fuel consumption, and lowers emissions.

What Does an EGR Valve Do?

The EGR valve recirculates exhaust gas through the engine, through the intake. This process reduces nitrogen, which is beneficial because of its negative impact on the environment. 

The EGR valve can function differently depending on whether a car runs on gasoline or diesel fuel because the machinery operates differently. 

Types of EGR Valve

There are a few different types of EGR valves, depending on the various car systems. 

Diesel High-Pressure EGR Valve 

  • Diverts the high-flow, high-soot exhaust gas
  • Diversion happens before entering the diesel filter 

Diesel Low-Pressure EGR Valve 

  • Diverts the exhaust gas after it has passed through the diesel particulate filter 
  • Has a lower flow
  • Clean of soot 
  • Gas is passed back through a pipe to the inlet manifold 

Gasoline EGR Valve 

  • Diverts the exhaust gases
  • Cylinder depression creates a vacuum, which can draw the exhaust gas in 
  • The EGR opening and closing regulates the flow of the gas 

Vacuum Operated EGR Valve 

  • The vacuum can open and close the EGR 
  • Some of them feature a sensor for feedback, informing the ECU of the positioning of the valve 

Where Is the EGR Valve Located?

The EGR valve is located in the engine’s inlet manifold, however, on some cars, it is located lower down near the exhaust manifold. 

How to Clean an EGR Valve

Cleaning the EGR valve is a straightforward process that can be done by almost anyone with the right tools and preparation. 


  • Safety glasses 
  • Acid-resistant gloves
  • EGR valve cleaner 
  • Pipe cleaning brush 
  • Scraper 
  • Cloth


  1. Find the valve and unplug all electrical connections attaching to or near the valve 
  2. Remove all of the screws mounting the valve 
  3. Remove the gasket, inspecting the condition while doing so. If it is in bad condition, replace it before putting it back after the EGR valve has been cleaned.
  4. Wearing your safety glasses and acid-resistant gloves, begin to spray the EGR valve cleaner onto the carbon deposits 
  5. You will need to remove all of the carbon build-up with the spray, using a pipe cleaning brush and a scraper too 
  6. Continue this process until all of the carbon deposits have been removed 
  7. Clean the surface with a fresh cloth to remove any excess 
  8. Place the EGR valve back and reconnect all of the previously disconnected attachments 
  9. If the engine light is off then your clean was successful! 

Why do EGR Valves Fail?

EGR valves fail because of accumulated build-up deposits of carbon. When this happens, the temperature is raised, and it causes a disruption to the flow of gas. The build-up needs to be removed and cleaned for the flow to continue normal operation.

EGR valves usually need to be cleaned and unclogged for them to function properly again, as replacing them is not a frequent occurrence. 

Symptoms of a Faulty EGR Valve

Sometimes an EGR valve will need to be cleaned rather than replaced. If you can smell fuel under the hood of the car, then have a mechanic inspect your car because they will be able to advise whether it is time to replace or have a deep clean. 

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If there are performance issues with the engine, or the engine light is on, then the EGR valve could be to blame. Usually, when EGR issues arise, the vehicle will have problems with acceleration, suspension, and might experience turbo boost pressure leaks. 


What Happens When an EGR Valve Goes Bad?

When an EGR valve goes bad, the performance reduces significantly. Your car will begin to function abnormally, sometimes creating a rattling noise which will be one of the initial signs of an issue. You will also likely experience problems with the everyday operation of the vehicle like acceleration, and notice an excessive smell of fuel from the bonnet. 

Increased use of the vehicle while the EGR valve is malfunctioning can cause a reduction in power, further issues with acceleration, and a decrease in fuel efficiency. Because of these issues, fuel emissions will also increase and you will be running out of fuel faster than normal. 

How Much Does It Cost to Replace an EGR Valve?

The average cost for replacement is between $250 to $350. This cost is dependent on the type of vehicle and specificities such as model, year, make, and the system of the car as well. 

This total cost factors in the cost of the physical part required, as well as the cost of labour needed to perform the replacement. 

How Often Does an EGR Valve Need to Be Replaced?

The EGR valve needs to be replaced around the 80,000km mark - although this is an average estimated recommendation. It is always best to have it inspected when you have your routine maintenance. 

How to Replace a Faulty EGR Valve?

It takes an hour or so to replace so make sure you have allocated enough time in your schedule to do it properly, so you don’t feel rushed. 

Follow these steps to replace your faulty EGR valve yourself:

  1. Remove the cover of the engine 
  2. Find the electrical cable on the valve and loosen it 
  3. Remove the electrical connections and/or vacuums, inspect their conditions and possible signs of damage 
  4. Find the screws fastening the valve and remove these carefully 
  5. Thoroughly inspect the EGR valve for damage, carbon build-up, or erosion
  6. If the EGR is in a repairable condition, remove it and begin cleaning it
  7. If it is in bad condition and you have a new EGR valve to insert, follow all of the factory instructions accompanying the part
  8. You will need to do a diagnostic check after the EGR valve has been installed and all the lines and connectors have been reconnected
  9. If the engine light is still on, it is recommended you take the car to a mechanic

Can I Replace My EGR Valve Myself?

Yes, replacing an EGR valve is a fairly straightforward exercise that can be done by a DIY mechanic with basic tools and understanding. 

If you are struggling to find a mechanic, then Enji are here to help you find the perfect mechanic for your needs in your local area.


If you suspect your EGR valve is playing up, inspect it first because the simple solution is most likely that it just needs a clean! If the condition of the EGR valve looks dire, then have it inspected by a mechanic to determine whether or not it is time for it to be replaced. 

If you feel confident and capable enough to replace it yourself, it is a straightforward DIY. Otherwise, take your car to your trusted mechanic to have them get it into working condition.