Content

• Steps
• Method 1 of 2: Cleaning the Mechanical EGR Valve
• Method 2 of 2: Cleaning the Electronic RVG Valve
• Tips
• Warnings
• What do you need

Back in the 1960s, automakers began installing exhaust gas recirculation (EGR) valves on cars to reduce nitrogen oxide emissions. The EGR valve circulates a small amount of exhaust gas into the combustion system. The heat from the exhaust gases heats up the combustion chambers very quickly, while the spent inert gases keep the chambers from getting too hot when the engine is fully heated. Both the mechanical and electronic EGR valve open and close to regulate the gas flow. If left open, excess vacuum will cause the engine to idle. If the valve is closed, an explosion can occur in the combustion chambers. The resulting knocking and humming will reduce mileage and engine longevity. To achieve stable engine idling, sharp acceleration and reduce tapping, it is necessary to clean the EGR valve.

Steps

Method 1 of 2: Cleaning the Mechanical EGR Valve

1. 1 Disconnect the vacuum hose and inspect it for wear (cracks and weak spots), then use a carburetor cleaner spray or pipe cleaner to clean the carbon deposits if the carbon is hard or coking.
2. 2 Loosen the bolts that secure the RVG valve to the engine. Inspect the bottom valve plate gasket. If it is not frayed or cracked, you can continue to use it.
3. 3 Take carburetor cleaner and a small stiff wire brush, toothbrush, or pipe cleaner and clean the metal exhaust return pipe and valve inlet port (usually a small hole with a spring loaded pin or king pin) to remove carbon deposits.
4. 4 Clean the inlet port connecting the valve pipes to the engine (intake manifold) when the EGR valve is closed.
5. 5 Make sure that the vacuum baffle moves freely, return the EGR valve to its place and connect the vacuum hoses and exhaust pipe.

Method 2 of 2: Cleaning the Electronic RVG Valve

1. 1 Disconnect the negative cable from the battery so that no current flows through the system so as not to short the electronic part that controls the valve.
2. 2 Disconnect and disconnect all sensors and electrical connections with the hoses.
3. 3 Loosen the bolts to remove the RVG valve and gasket.
4. 4 Inspect hoses and gasket for wear and replace if necessary.
5. 5 Clean the valve and hoses with a carburetor cleaner, and brush off any deposits that have accumulated in the hoses and in the small king pin hole. Do not apply cleaner to electrical connections and sensors! But if you see them corroded, buy a can of electronics cleaner and dielectric grease.
6. 6 Put the RVG valve and gasket back in place and screw them down. Also, reconnect all electrical connections and sensors, and reconnect the hoses.
7. 7 Connect the negative wire back to the battery.

Tips

• Read the user manual for a check schedule, although you can inspect the EGR valve yourself every 20,000-25,000 kilometers.If you cleaned the valve and it clogs up earlier than usual, take your car for diagnostics. Your engine may need to be tweaked a little more if it builds up that much soot so quickly.
• If you can disconnect the RVG valve from other assembly parts (hoses and electronic connections) in order to spray the valve with carburetor cleaner, you can soak it in it so that the accumulated carbon is completely removed both inside and outside the valve.
• When spraying or soaking the valve, keep the old gasket away from the cleaner if you still want to put it back in place, as it can harm it.

Warnings

• Inspect and replace the EGR valve outdoors or in a well-ventilated area to reduce exposure to carburetor cleaner vapors and exhaust fumes.

What do you need

• Repair manual specifically for your brand and model of car
• Manual vacuum pump (for mechanical EGR valves)
• Control mirror (for mechanical RVG valves)
• Pipe cleaner, toothbrush, or other small, stiff brush
• Carburetor cleaner
• Hand tools: wrenches, couplings, ratchet and screwdriver
• Replaceable gasket (not for all, but only for some car models)