If you notice rough idling or the distinct smell of fuel coming from under the hood, there is a good chance that you have an issue with the EGR valve. Instead of replacing the device, you may want to clean it first. The symptoms you observe may not be an indication of a faulty EGR valve. They may indicate a dirty one. In this article, you’ll learn how to clean EGR valve.
What is an EGR Valve?
EGR stands for exhaust gas recirculation. Based on this definition, this valve either allows or prevents the re-entry of exhaust gases into the combustion chamber through the intake manifold. If it allows exhaust gases back into the combustion chamber, then it can lower the temperature in the chamber.
Why Clean an EGR Valve?
It is important to understand the function of the EGR valve so you will appreciate the value of using the right EGR valve cleaner.
In our definition, we said that the valve recirculates exhaust gases back into the combustion chamber via the intake manifold. The air that enters the intake manifold contains 78 percent nitrogen, 21 percent oxygen, and about 1 percent of other elements. When these elements combine with the fuel in the combustion chamber, they cause a chemical reaction resulting in a controlled explosion.
This controlled explosion or combustion can have a temperature that exceeds 2500 degrees Fahrenheit. This also burns the different elements in the fuel-air mixture, creating nitrogen oxides in the process. These gases are detrimental to human health as well as the environment.
The job of the EGR valve is to take some of the exhaust gases and divert it back to the intake manifold. This decreases the temperature in the combustion chamber, preventing the formation of nitrogen oxides.
There is one ‘expected’ consequence of this recirculation process. The recirculated exhaust gases can build up on the inner surface of the EGR valve. Over time, this can form a thick and hard wall of carbon deposit. This can prevent the valve from either opening or closing. It can also block the passageway.
It is for this reason that learning how to clean EGR valve is the crucial first step in addressing the problem.
How Do You Know You Need to Clean the EGR Valve?
Car manufacturers recommend cleaning the EGR valve and the different passages every 50,000 or so miles. However, you do not have to wait for this period before you start cleaning the valve. If you notice any of the following symptoms, then it would be wise to clean the device.
- Unusual noise from the engine like knocking, tapping, or pinging
- Engine stalling
- Rough idling
- The Check Engine light comes on
- Smell of fuel while the engine is running
- Poor fuel economy
- Failed emission test
How to Clean the EGR Valve
Can you clean an EGR valve? Yes, you can. Cleaning the EGR valve is easy. You do not need to drive your vehicle to a repair shop to have the device cleaned. All you need are a few hand tools, some elbow grease, and a good quality EGR system cleaner. Here are the steps:
- Safety First
Always start by parking your car on a flat and even surface. Put your car in the Park position and engage the parking brakes. Turn off the car’s engine. Remove the cables on the negative terminal of the car’s battery.
- Locate the EGR Valve in Your Car
There are three types of exhaust gas recirculation valves. This often depends on the model and make of your vehicle.
Older cars often have a vacuum-controlled unit. This looks like a round, semi-flat, and 3-inch thick metal disk. There is a vacuum hose that’s connected to the top of this device.
Newer cars can have an electronic vacuum-controlled valve. This looks like the vacuum-controlled unit, except that it has a small sensor on top. You will also see an electrical harness connecting the sensor to the car’s electrical system.
There are also modern cars that have electronic-controlled digital valves. They may come in the form of a block or a cylinder that comes with an electrical harness and sensors.
Check your owner’s manual for the type of EGR valve that your car has. You can also see from the manual where the device’s precise location is under the hood. In general, the EGR valve can be either on the side of the engine or on the top. The manual can also provide a picture of what you need to look for.
If you no longer have your manual, you can check automotive online resources. They can show you a picture of the EGR valve that is specific to the model and make of your car.
- Remove the EGR Valve
Locating the EGR valve is one thing; removing it is something else. Some of these devices are quite difficult to reach. There can be different hoses, engine parts, and accessories that may be in the way. You will have to remove these first before you can start removing the EGR valve.
If the device comes with a vacuum hose, make sure to disconnect the hose very carefully. This is a very thin hose and is subject to damage if you do not handle it in the correct manner. Check the vacuum hose for signs of hardening, softening, splits, or cracks. If you notice any of these, then you need to replace the vacuum hose.
Unplug electrical connectors that may be connected to the valve. Spray WD40 on the bolts to make it easier to unscrew. Let the solution sit for a while so that it can penetrate the rust that may have built up in the bolts. When ready, remove the mounting bolts of the valve. Some devices come with 2 bolts; others, 4. Check if the EGR valve also has a pipe that leads to the exhaust manifold. If there is, disconnect this from the exhaust manifold.
Remove the valve including the gasket. Check the condition of the gasket. If there are cracks or signs of uneven wear, replace it. Otherwise, you can recycle it.
- Clean the EGR Valve
Wear a pair of acid-resistant gloves. You will also need safety glasses. It would also be a good idea to wear a mask. Remember that you will be removing carbon deposits from different sections of the valve. These can get airborne, allowing you to inhale them.
Get your EGR valve cleaner and spray the carbon deposits. A good alternative to an EGR system cleaner is a carburetor cleaner. If any of the cleaning solution gets in contact with electrical components or plastic parts, you should wipe this off at once.
Use a pipe cleaning brush and a dull scraper to scrape the carbon buildup. Make sure to remove carbon buildup from the valve’s surface and its entry and exit ports. Also include the EGR system’s pipe and other ports. Complete the carbon removal process with a soft brush. Use a clean piece of cloth to wipe the surface. You may have to repeat the process several times to make sure that no carbon deposits remain. Remember to avoid gouging sealing and mounting surfaces. This can cause a leak in the system.
If the carbon buildup is difficult to remove using a pipe cleaning brush, you may want to soak the valve in the EGR system cleaner for a couple of minutes. Do not immerse the plastic components and electrical parts. Repeat the brushing process after soaking the device for 3 to 5 minutes.
If you think that carbon deposits may have accumulated in the intake manifold as well, then you can also spray it with the EGR valve cleaner. However, it is best to check the cleaner’s manufacturer if you can do this. Otherwise, you may need a different kind of cleaning solution.
- Replace the EGR Valve
Once you’ve cleaned everything, you can start putting the EGR valve and everything else back into their original places. If you have to replace the gasket, now’s the best time to do so. Screw the bolts and tighten them using the correct torque. Reconnect the vacuum hose and the pipes. Also reconnect the electrical harness, if any.
- Check the Operation of the EGR Valve
Part of learning how to clean EGR valve is making sure that the device works as intended after cleaning. Reconnect the car’s battery and start the engine. You can check the instrument panel for the Check Engine display. If there is none, then you have done a good job. You can also use an appropriate diagnostic tool to make sure that everything is in working order.
The best way to ensure that the EGR valve cleaning worked is to drive your car. The car should run at idle in a smooth manner. There is no engine stalling or annoying sounds coming from the engine. You should also not smell fuel anymore.
Can you clean an EGR valve? Yes. Do you need a professional to do it? No. A good quality EGR system cleaner and a few basic tools are all you need to clean this device.
Sources:
- How to Clean an EGR Valve – Your Mechanic
- How to Clean Your EGR Valve – Wiki How
