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How to Clean an EGR Valve

Omkar Phatak
Here are some instructions, detailing the EGR valve cleanup of your car. By scheduling periodic maintenance of the valve, you can achieve the twin objectives of reduction in emission and optimization of engine efficiency.
Controlling emission of polluting gases from a car exhaust was a major challenge for automobile designers. A technological breakthrough that achieved this purpose was the EGR (Exhaust Gas Recirculation) mechanism fixed in car engines.
The EGR valve cleaning instructions provided further will apply to most automobiles but not necessarily all of them, considering the differences in design approach of various manufacturers.

EGR Valve Cleaning Instructions

The EGR valve can cause a fall in engine efficiency and seriously compromise fuel economy of a car, due to carbon deposition and blocking caused by particulate matter. Clogging can cause the diaphragm inside the valve to fall into disrepair.
The valve is supposed to close and open during an engine cycle to release exhaust gases in a feedback loop, to keep the engine temperature down. If the valve becomes unresponsive and stays open or closed, the engine pings or knocks, driving down efficiency. That necessitates valve cleaning once a year.
Here is a short guide. You will require a wrench set, socket set, scratch awl, cleaning brush, ratchet, carburetor cleaning fluid, a vacuum pump (optional) and Phillips screwdriver for the job. It's recommended that you wear safety glasses and gloves for protection.
Step 1: Disconnect the car battery's negative terminal. Open the car hood and locate the EGR valve. It usually lies on the engine side and has a vacuum hose on top and an electrical connector. Refer your car manual for the exact location.
Step 2: Remove the vacuum line attached to the EGR valve, along with the electrical connector. If the vacuum hose appears to be worn out or damaged, it should be replaced immediately. You will also have to remove the pipe that connects to the valve bottom. With all these connections removed, the valve itself can now be removed for inspection and cleaning.
Step 3: Remove the entire valve assembly by unscrewing the nuts holding it to the engine and the gasket, using wrenches. Now you can work on the valve.

Step 4: Disconnect the solenoid that's usually attached at the valve top, with a screwdriver.
Step 5: With the help of a scratch awl, clean the bottom passage of the valve mechanism. This will get rid of the carbon deposits inside. If there are no electronic connections associated with the valve, you may soak the entire valve body in a cleaning fluid. However, in case you have an electronic valve, soaking is forbidden.
Step 6: Spray the carburetor cleaning fluid on the valve, barring the electrical connections. Using a brush, clean every accessible surface of the valve body.
Step 7: Also clean the pipe attached to the bottom passage. In case the valve gasket is damaged, replace it. Otherwise just clean it and you are done. Let the valve dry. Vacuuming it will remove fine particulate matter, besides helping it dry quickly.
Step 8: With that, you have finished cleaning the valve. Rest of the job is putting it back as it was. To do this, you must retrace your steps and go in reverse, by connecting the solenoid, pipe, vacuum hose, electrical connector and then reattach the valve in its place in the proper reverse order.
With that, your cleaning job is finished entirely. Reconnect the car battery and you are good to go.

About EGR Valves

The concept of 'Exhaust Gas Recirculation' evolved out of the need to restrain the emission of nitrogen oxide compounds from a car's exhaust. Besides causing smog, these compounds are poisonous gases that cause adverse effects in many biological systems that come in contact with them.
Smog reduces visibility. That's why reduction of their emission through the exhaust was a high priority task. Nitrous oxide is copiously produced in high temperature conditions inside an engine, in a high concentration mixture of nitrogen and oxygen. Automobile engineers developed the valve mechanism to eliminate the problem of nitrogen oxide production.
This was achieved in the following manner using a feedback mechanism. A portion of the exhaust gases are fed back to the engine's combustion chambers. This causes a drop in the temperature of the gasoline-air mixture and reduces the production of nitrogen oxide compounds.
The valve's function is to control when and how this feedback is supplied to the engine. The exhaust gases are not fed back when the engine is in high RPM mode or when it is almost idling. This ensures that the car engine's efficiency is not compromised. Thus the valve's functioning is crucial for maintenance of engine efficiency.
A clean up job of an EGR valve, with a repair center will cost anywhere between $150 and $600. It is recommended that the valve be examined after every 12,000 to 15,000 miles of running. In your yearly car maintenance campaign, make sure that the EGR valve cleanup is included.