The TDI EGR valve functions as part of the emission control system on turbocharged engines, commonly found in Volkswagen and other models. Oil vapours and soot collect inside the EGR valve, piping and intake manifold to form a film and build-up. The accumulation can become extreme, which leads to reduced airflow. The reduced airflow ultimately causes poor performance and acceleration response. Large chunks of build-up can break free and enter the combustion chambers, causing damage to major engine components. The TDI EGR valve should be inspected and cleaned routinely.
- Skill level:
Things you need
- Owner's repair manual
- Socket set (metric)
- Socket extension
- Universal socket
- Ratchet wrench
- Carburettor cleaner
- Butter knife (custom sharpened)
- Flat file
- EGR gasket (if applicable)
Place the vehicle in park or neutral, depending upon your transmission type. Set the emergency brake and raise the hood. Use a socket to disconnect the negative battery cable. Use a small socket or screwdriver to remove the upper and lower engine cover plenums and set them aside.
Refer to your owner's manual for the location of your EGR valve. It will look like a fist-sized metal diaphragm, with a large, black air supply hose attached to it. It mounts directly to the end of the intake manifold. Use pliers to unfasten the spring clamp to the air supply hose that attaches to the EGR valve.
Use pliers to loosen the spring clamp on the other end of the air supply hose at the intercooler box. Pull the vacuum hose off the EGR diaphragm nipple and wedge it aside. Look directly underneath the EGR valve neck and you will see an exhaust cooler line attached with two cap hex screws. Remove the screws with a small socket or screwdriver. Pull the flange away, but do not disturb the metal gasket underneath.
Find a socket to fit the three bolts that hold the EGR valve to the intake manifold. Use an extension and wrench to loosen and remove each bolt. Use a universal socket to reach the bolt at the lower left side. Gently pry the EGR valve away from the manifold with a screwdriver, without disturbing the gasket. Soak both the intake and exhaust ports of the EGR valve with carburettor cleaner and let it set for 15 minutes.
Use a flat file to bring a butter knife edge to sharpness at the tip and one inch below the tip. The blade does not have to be razor sharp. Spray more carburettor cleaner inside the EGR valve ports. Use a circular scraping motion with the butter knife to remove all carbon build-up inside the EGR ports. Do not touch the flapper valve with the knife. Use a toothbrush soaked in carburettor cleaner to clean the flapper valve on both sides. Remove all carbon and soot.
Wipe the interior of the EGR valve with clean rags. Do not leave any residue, carbon particles or soot inside any part of the valve. The valve must also be completely dry. Place the valve back on the intake manifold and replace the three mounting bolts. Tighten the mounting bolts with the socket, wrench, extension and universal socket.
Line up the exhaust cooler line and screw in the mounting hex screws by hand. Tighten the hex screws with a screwdriver or small socket. Plug the vacuum line back on the diaphragm nipple. Connect the air supply hose at the intercooler box and at the EGR valve neck. Compress the hose spring clamps with pliers and slide them over the hoses.
Set the engine cover plenums back into position and replace the screws. Use a socket or screwdriver to tighten the plenum screws. Reconnect the negative battery cable with a socket. Start the engine and check for vacuum leaks.
Tips and warnings
- For a professional cleaning of the EGR valve, take it to a shop that specialises in ultrasonic cleaning and have it done there. This process guarantees the removal of all microscopic particles.
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