A: In most vehicles, the EGR valve sits on a pipe that connects the exhaust manifold or intake manifold. Vehicles fitted with a carburetor will usually have the valve located behind the carburetor for optimum/even EGR feed to all cylinders.
The EGR valve’s location can vary according to the vehicle’s model and model year. In the 2001 Ford Excursion, the valve sits on the intake manifold’s top behind the throttle body. Meanwhile, the 2005 Dodge Ram 1500 EGR valve can be found on the right front cylinder head beside the alternator. And the EGR valve of the 2005 Chrysler Town & Country is located above the alternator on the sideways-mounted engine’s left side.
The EGR valve will always be mounted so that it delivers exhaust gas evenly to all cylinders. This is done by putting it right past (behind) the throttle body on the intake or by having a small EGR feed port in each intake runner. So, if you look near the throttle body, you’ll typically find it bolted to the manifold in that area, and you’ll usually see a metal feed pipe from the exhaust leading to it.
The exhaust gas recirculation (EGR) valve is a vital part of the emission control system. It returns about 5% of the exhaust gas to the combustion chamber when the engine is loaded and not idling. If the EGR is flowing at idle, the intake manifold will get very hot and the engine will idle extremely rough.
This recirculated exhaust gas lowers the combustion chamber temperature below 2500F by displacing some of the oxygen flowing through the intake manifold into the cylinders. Keeping combustion chamber temperatures below 2500 F reduces the formation of oxides of nitrogen during the combustion process.
The EGR valve is easy to access, so you can easily remove it for cleaning or replacement. However, there are vehicle models where the air cleaner duct or engine cover partially blocks the way to the valve. Use a Philips or standard screwdriver to unfasten the obstructing parts and move them out of the way.
You also have to disconnect the car battery’s negative terminal before doing anything. Some vehicles require you to enter a security code after you reconnect the battery, or else they’ll keep the electronics turned off. You can usually find the code in your owner’s manual.
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