How Can A Faulty EGR Valve Damage Your Car?

A driver needs to drive not only a well-maintained vehicle but also an eco-friendly one. To ensure both, one has to ascertain that their exhaust gas recirculation valve or EGR valve is fully functional and is working in sync with its EGR system. If your vehicle’s EGR valve is damaged, then it is not fit for driving around town. A damaged EGR valve can have adverse effects on your vehicle as well as your health. Not to mention, the harm it does to the environment is also significant. Hence, it is best for all vehicle owners to be aware of the symptoms and the effects of a damaged EGR valve. This article aims to do the same for all.

What does an EGR valve do?

The Exhaust gas recirculation system is responsible for managing the chemical and thermal exhaust of your engine. The EGR valve maintains your vehicle’s smooth operations while driving, especially for a longer period. It reduces the engine’s chemical emissions through the exhaust and lowers the engine’s temperature in the process.

The EGR valve particularly controls the Nox or Nitrous Oxide emission. This helps your vehicle burn out the unused fuel efficiently by recirculation a portion of the exhaust. This way, it lowers the number of harmful emissions produced by your vehicle.

How would you know that your EGR is failing?

Vehicle owners need to identify a faulty EGR valve at the earliest. Being aware and looking out for the following symptoms might be helpful in this aspect.

1. Fuel detonation noise

This happens when at a high RPM, the EGR valve system shuts down, causing a high temperature in the vehicle’s combustion chamber. It occurs due to the absence of the cooling effects of the exhaust gas. As the nitrogenous compounds are produced, detonation will increase, causing ignition of the fuel but without much of it burning. It will ultimately result in detonation noises inside the engine.

2. Rough idling

At low RPM values or when the engine is idling, the extra amount of exhaust gases causes engine damage if the EGR system stays open.

3. Nox emission

As the EGR system goes haywire, Nox emission increases significantly.

4. Erratic engine functioning

When multiple facets of the engine go wrong, the engine starts malfunctioning in its entirety.

What Damage Can a Faulty EGR Valve Cause

1. EGR valve can cause a misfire

A faulty EGR valve can cause a misfire all too often. It is usually caused by clogged passages inside your car’s intake. It will also diminish your vehicle’s power output. Oil vapors inside the engine increase carbon accumulation inside the exhaust gas recirculation valve, causing a stuck valve. Let us suppose the EGR valve remains open throughout. The high proportion of exhaust gas decreases the amount of air drawn inside. The control unit decreases the quantity of fuel injection hence the output of the engine. This all leads to a vehicle misfire when you’re driving.

A damaged EGR valve can cause a chain of adverse effects on other components of the vehicle. Especially one might observe black or grey smoke coming out of the exhaust pipe. If left unchecked, this can result in your car’s intake getting damaged and also affect its valves.

2. Faulty EGR solenoid

One of the most significant parts of the EGR system is the EGR solenoid. A faulty EGR valve can damage the EGR solenoid that can, in turn, cause performance issues of the engine. The engine check light would turn on then, and then the engine might knock and ping. When the EGR valve gets all knocked up, the EGR solenoid opens up, closing the connection between the intake manifold and the exhaust manifold.

What can cause an EGR valve to fail?

There can be multiple reasons for the EGR valve to fail while the vehicle is operating. They are mentioned briefly as follows.

  • · Poor management of vehicle engine
  • · Multiple numbers of short-distance drives leading to oil-water emulsion formation
  • · Damaged engine cooling system.
  • · Malfunctioning vehicle engine ventilation.
  • · Oil overfill


In case your vehicle is subjected to a faulty EGR valve, the best thing to do right away is get it tended to. If it is beyond repair, then having it replaced is the only way out. If it has affected more parts of your vehicle, then repairing costs will multiply. Bear in mind that driving around with a damaged EGR valve can be catastrophic to both your vehicle and the environment. Ensure that a correct diagnosis has been made on your vehicle’s EGR system before any replacement is made on it.