EGR Valve: What it is, how it works and how to prevent it from breaking down.

You might not recognize the term EGR valve. But the truth is, despite being a component almost unknown to most drivers, it's vital for the proper functioning of your car.

What is the EGR valve?

The EGR valve is responsible for recirculating a certain amount of exhaust gases back into the combustion chamber. This reduces the temperature and, consequently, the amount of pollutants emitted. This system, along with the particulate filter or catalytic converter, is used by modern cars to reduce the emission of pollutants and/or toxic gases into the atmosphere.

Symptoms of a faulty EGR valve

EGR valve failures are relatively common, especially in diesel engines. Why is this? Well, mainly because diesel engines are more prone to generating excessive carbon buildup. This excess carbon buildup tends to adhere to the valve walls, ultimately restricting the engine's airflow and reducing its performance.

This carbon accumulation can cause the valve to not respond correctly to commands from the ECU, as the buildup can prevent it from fully opening and closing.

Therefore, the car may experience difficulty starting in cold weather, jerking, or the aforementioned loss of power.

Tips to prevent the problem

The best way to prevent carbon buildup inside the intake valve is to drive at high RPMs—once the engine has warmed up—from time to time, as well as frequently taking a few kilometers on the highway. It is also advisable to clean the fuel injection system regularly and use high-quality engine oil.

EGR Valve Cleaning

The difficulty of cleaning the EGR valve depends on whether it's electric or mechanical. If your car has an electric valve, you'll need to take it to a workshop equipped with the necessary technology for cleaning. This typically involves machines that use ultrasound or hot water pressure.

If the valve is mechanical, you can clean it yourself by following these steps:

1 - Locate the valve using the instructions in your vehicle's manual.

2 - Remove the upper and lower engine air hoses.

3 - Once you've located the valve, remove the spring clamp and the air supply hose to the system, the intake manifold, and the exhaust manifold.

4 - After removing the valve, remove and discard the rubber gaskets between the valve and the intake and exhaust manifolds (to be replaced later). 5 - Once the valve is removed from the engine, we can proceed to clean it, either with carburetor cleaner or by immersing the valve in hot water. In either case, it should be left to soak for a few minutes for the cleaning to be effective.

6 - Once the carbon deposits are soft, remove them with a toothbrush dipped in carburetor cleaner or degreaser.

7 - Once the valve is clean, check that the intake manifold is clear. If it is not, we can clean it using a drill with a circular brush attachment.
Disabling the re-intake valve: a bad idea

Sometimes, when faced with a valve failure, many car owners decide to disable it in the ECU software. This disabling results in the restoration of power and the turning off of the malfunction indicator light on the instrument panel. However, we must warn you that if you disable the re-intake valve, your car will not pass the MOT test. Therefore, we strongly advise against this measure.

The Cost of a Replacement

Replacing a re-intake valve is among the most expensive repair operations. While replacing one valve with another is usually quite simple, the price of the valves ranges from €300 to €1200. Therefore, at ecumotorstock, we recommend trying to clean it first; and if this is not possible, then proceed with the replacement.