What is an EGR valve?

Automobile manufacturers have made considerable progress in their efforts to reduce the greenhouse emissions of modern vehicles. However, even before the inception of hybrids, electric cars and catalytic converters, EGR valves were doing their part to make cars more eco-friendly.

EGR stands for “Exhaust Gas Recirculation.” The EGR valve reroutes some of your vehicle’s exhaust back into the engine’s combustion chambers. This benefits your vehicle in two ways. Firstly, recirculation gives your engine a second chance to fully expend unburned fuel in your exhaust. This sharply reduces the amount of harmful greenhouse gases produced by your vehicle.

The second benefit is a reduction in combustion reaction temperature. The EGR valve helps your engine run cooler by regulating the oxygen flow into your engine’s combustion chambers. This dramatically reduces the formation of harmful gases, many of which are only created at very high reaction temperatures. This is how your EGR valve makes your vehicle vastly more environmentally friendly without significantly impacting on its power or performance. When EGR valves fail, the effect is not simply an increase in greenhouse gas emissions. Faulty EGR valves also contribute to poor fuel efficiency and can cause potential engine problems. Thus it is important to install a new EGR valve as soon as possible if you think your current valve is wearing out or faulty.

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How can you tell when an EGR valve requires cleaning or replacement?

Over time, a large amount of carbon build-up can appear in the EGR valve housing and on the valve itself. This sediment may block the valve and seal it in an open or closed position. If stuck open, the valve will let too much exhaust into your engine’s combustion chambers. This can stifle the explosive reaction that powers your vehicle. The results are acceleration irregularities, rough idling and poor fuel efficiency. If the valve is stuck closed, a surplus of oxygen will enter the engine’s combustion chambers and cause the engine to run hotter than intended. A hot-running engine can lead to increased emissions and engine “knocking.” In some cases, the EGR valve may be extracted and cleaned, but most times it’s safer to simply install a new EGR valve.

Tips on replacing your car’s EGR valve

Your vehicle’s EGR valve will likely be located near the top or rear of the vehicle’s engine. Refer to your owner’s manual for its exact location. Allow your vehicle’s engine to cool for several hours. Afterward, disconnect the car’s battery terminals. Locate and label the vacuum hoses connected to the EGR valve and remove them. Also remove any electrical cables attached to the valve. Loosen the nuts connecting the valve to the engine and remove it. Next, clean the EGR valve mounting surface of any rust or carbon build-up and install the new valve. Replace the nuts, wires and vacuum hoses exactly as you removed them.

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