How to Replace an EGR Valve

Emission control is a major concern for the automobile industry. There have been many innovations that have helped in bringing down emission and air pollution levels. One such innovation is the EGR (Exhaust Gas Recirculation) valve technology.

This technology was developed out of the need to reduce nitrogen oxide emissions from automobiles. To achieve this objective, a feedback mechanism was developed. This technology reduces nitrogen oxide emission, by inhibiting the very process that leads to its creation. The technology works in the following manner.

A portion of the exhaust gases, emitted from the car engine, is fed back to combustion cylinder. This exhaust gas feedback, displaces the combustive mixture of gases by volume and leads to a drop in the heat of combustion, generated in every cycle.

Without compromising to a great degree, on the pressure generated in the cylinder, the combustion cycle occurs at a lower temperature. Nitrogen oxide compounds are formed faster, from a high temperature mixture of oxygen and nitrogen.

Since exhaust gas recirculation valves reduce the combustion temperature in the cylinder, comparatively lesser amount of nitrogen oxide is created, which is responsible for smog.

EGR valves are fitted in the engine assembly, to establish and control this feedback mechanism. The valve only lets in exhaust gases, in conditions when the car engine is not idling or when it does not require high combustible fuel concentration.

This ensures optimum performance, when RPM demands are high and prevents a rough performance, when the engine is idling. Modern valves are electronically operated.

In case the valve malfunctions, engine efficiency drops down drastically. The biggest problem is caused when it stays stuck open and messes up the engine's efficiency.

In such a situation, engine cylinders get flooded with exhaust gases, leading to a reduction in oxygen availability. This compromises the engine functioning totally. That is why, a faulty valve needs immediate replacement.

Replacing EGR valves is a task that can be carried out quite easily, if you are willing to apply yourself. The tools you'll need are a socket set, wrench, screwdriver, a specialized tool called carburetor cleaner, and a small drill bit. Along with these, you'll need a new valve and a new gasket that accompanies it.

Firstly, disconnect car battery and locate the position of the valve. Next, you need to make some more disconnections. Remove the vacuum hose, air supply hose, and rest of the electrical accessories, using a screwdriver.

To detach the valve unit, you'll need to remove the bolts that keep it in place. Using a wrench, remove these EGR valve mounting bolts. Observe the valve and make sure that it is totally beyond repair. If it is, then go ahead and replace it with a new valve, along with a new gasket, if needed. Mount the bolts back in place, to secure the valve in position.

Next, you need to retrace your actions and replace all the electrical accessories and components that you removed initially. Reconnect the air hose and restore other connections. Restore the car battery connection. This completes the replacement procedure. Pulling off this task on your own, reduces the replacement cost.