Automotive Maintenance And Detailing


Automotive Maintenance And Detailing

Why do we need EGR valve cleaning?

EGR Valve cleaning is another vehicle maintenance which car owners should pay attention to, especially if you are using a diesel vehicle, as with older gasoline engines, EGR valves need cleaning as well.

How important is the EGR valve to the operation of the car engine? Which is why car owners should understand the system.   Because in addition to reducing pollution in the air, if the system fails, it will seriously affect the engine.

You may end up paying more engine repairs than the valve cleaner and EGR valve cleaning cost.

Flushing the EGR valve is something car owners can do on their own if they have a basic understanding of re-combustion exhaust gas recirculation.

We will describe the operating system, equipment location, proper cleaning times, and cleaning methods to ensure that your car’s engine is running smoothly.

What is the EGR system ?.

EGR System Diagram

EGR or Exhaust Gas Recirculation is a system for reducing pollution from the exhaust gas of both gasoline and diesel car engines by mixing some of the exhaust gas with oxygen in the combustion chamber to reduce the level of toxic gas emitted through the exhaust pipe.

The engine’s combustion chamber at temperatures of 2,000 to 2,500 ° F produces highly toxic gas, nitrogen oxides(NOx), and carbon monoxide. This gas will drop if the temperature of combustion chamber is not too high. Therefore, cars without the EGR system will release such toxic gas directly into the atmosphere, affecting people and the environment.

The reason for the high temperature of the combustion chamber is the presence of large amounts of oxygen as the combustion fuel mixture. While the engine is running normally, the ECU determines the low oxygen or lean mixture. But when the driver needs engine power, for example, when accelerating, the ECU adjusts the oxygen mixture more. That causes more toxic gas.

The EGR system works by mixing some of the exhaust or inert gas with oxygen to reduce the concentration of the fuel mixture in the combustion chamber. The benefits are lower temperature, less black smoke, less toxic gas. But the disadvantage is reduced engine power.

When EGR re-regulates the exhaust, the exhaust will flow through a valve. That is the EGR valve we talked about it.

The electric EGR valve acts to trap or allow gas to flow through the ECU’s control.

When exhaust flows through the EGR valve for a long time, such as 50,000 to 70,000 miles, exhaust soot will accumulate at the valve. This valve will not be able to move if the amount of soot is too high.

What if the EGR valve doesn't work?

No matter the valve is stuck in an open or closed stroke, it has a direct negative effect on the engine’s combustion system. Such abnormal symptoms, such as


 – vibrating engine

 – The engine operation is not smooth.

 – There is a lot of exhaust and black smoke.

 – Unusually noisy engine such as a knock, tab sound

 – Engine light is on

 – High fuel consumption


So you can see that EGR has a significant role to play in helping reduce air pollution. Many countries have laws regulating levels of automobile exhaust pollution. Modern cars, therefore, need to reduce toxic gases in various ways.


Most modern cars with EGR systems are diesel vehicles, although it originally invented and used on petrol and diesel vehicles. That’s because today’s gasoline cars have developed an exhaust combustion control system using a variable valve timing system.  Today, a small number of gasoline vehicles install with the EGRs.


The variable valve timing system controls the intake and exhaust valves to open or close at the time specified by the ECU. Such opening and closing will cause the combustion chamber temperature to increase or decrease. That will result in the engine power required by the engineer and directly reduce the toxic gas, nitrogen oxides, and carbon monoxide.


In addition to reducing the toxic gas content by the combustion chamber’s temperature control method, modern vehicles use catalytic converters to filter the exhaust gas.

How often should we clean the EGR valve ?.

As we mentioned earlier about the cleaning schedule of the EGR valve, usually, you should seek advice from a technician of the car brand you are using.   In the owner’s manual, there are no details on when to clean, as the manual only tells about general maintenance that car owners should know about it.

Service center technicians will know when the equipment is cleaning scheduled.

In everyday use, you should clean the valve every 50,000-70,000 miles. It is a considerable distance for exhaust soot to settle on the valve.

Cleaning before the engine shows a fault is better than waiting for it to happen.   Because you might not realize, it is the cause of a clogged valve. You or the technician may waste time and money analyzing the cause and replacing unrelated parts.

A dirty & stucked EGR valve after 50,000 miles

How to clean the EGR valve ?.

As said, the EGR valve brings the exhaust back to the intake chamber for repeated combustion. Therefore, the EGR system equipment installs between the exhaust channel and the intake passageway. The round shape EGR valve installs here where you may notice it immediately from the outside or have to remove the entire unit to access the internally installed valve.

We cannot recommend the exact installation location of the EGR system as it depends on the design of each vehicle. But once you understand the principle of operation, it’s easy to determine where it should be.

You can easily find EGR’s information in your car from the Internet, YouTube, or ask a mechanic.

In modern cars, the valve position sensor has equipped. You may be looking for a cable for a sensor switch in the area. And you look for a small vacuum tube that connects to the valve.

The valve is powered by suction from the vacuum hose to open and close the valve with an ECU-controlled actuator.

You would clean the valve by removing as much soot as possible first. Next, you should use a commercial EGR valve cleaner to clean the valve stem.

The picture shows exhaust pipe line of EGR system
A vacuum hose connected to the EGR valve

Cleaning steps.  Once you locate and now remove it.

  1. Wear gloves. We recommend using rubber gloves rather than cloth gloves.
  2. Prepare a container to hold the cleaning solution and dirty soot.
  3. Scrape as much exhaust soot trapped in the EGR pipe
  4. Locate the valve to be cleaned.
  5. Use a small brush such as a toothbrush to brush soot on the valve stem.
  6. Spray the EGR valve cleaner and brush thoroughly. Make sure the soot is gone.
  7. Move the valve stem that it can move up and down smoothly.
  8. Clean both inlet and outlet of the exhaust on the EGR device.

  9. Clean the intake manifold and throttle valve that is usually attached to the EGR manifold.

  10. Install all the equipment back to the original place and start the engine to see if it works as smoothly as usual or not.

Sometimes rinsing with this special cleaner may need to be soaked for some time. That will make it easy to brush off the soot.

In most cases, an EGR cleaning works well without having to pay for replacement parts. If, unfortunately, the EGR is damaged, such as the valve actuator is broken, you will need to replace it.

Reassembling the original position is an easy job. You will have to pay attention to the fastening of the bolts, install the wires, and the vacuum tubes firmly back. Otherwise, the valve system does not work as it should.

Another caution is that, as you remove the equipment and wash it, you should find a rag or paper to cover the intake and exhaust vents on the engine. It is to ensure that no foreign objects penetrated the engine.

The EGR valve after cleaning


You can clean the EGR valve yourself. But if you are not comfortable, you can take the car to a mechanic at the service center to clean it. Of course, there are costs for removing and washing. Hourly wages are all you need to pay. You should check the wage cost of your local garage first.

If your vehicle is under warranty, you should not expect the EGR cleaning to be on the mileage-based maintenance list. It is a time-consuming task for a workshop mechanic with a large number of repaired vehicles. If necessary, you may request a technician to open a cleaning job and pay for the service.

The EGR system is vital to reducing air pollution. It has been designing to work with gasoline and diesel engines. But nowadays it is mainly used in diesel engines.

Some car owners are blocking the EGR as they want the car to be powerful. The result is that more toxic fumes are released and are illegal in many countries.

We hope that once you understand the basic working principles of a system, you will be able to maintain it and keep it working as it should be. Because besides helping to prevent air pollution from high to a dangerous level, you can also keep your car ready for use when needed.

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