Ashes and combustion residues in the exhaust collector can cause irregular operation of the EGR valve, requiring replacement.
The EGR valve (exhaust gas recirculation) is a device designed to redirect a portion of the exhaust gases back into the intake manifold in order to reduce the combustion temperature and thus reduce the formation of nitrogen oxides. It exists in most internal combustion engines, whether diesel or gasoline. The amount of exhaust gases reintroduced into the engine is controlled by a diaphragm vacuum valve (or electronic control in newer engines), which is open when the engine is operating at partial load and closed when it is under full load. Ashes and combustion residues in the exhaust collector can cause irregular operation of the EGR valve and may require replacement in order to maintain its effectiveness in controlling NOx emissions or to avoid compromising engine performance. The black smoke coming out of the exhaust may indicate an open position, as excessive use of the valve results in the overproduction of particles and soot. In the closed position, the valve no longer functions and the emission warning light may come on.
The experts at Oscaro explain how to clean a dirty EGR valve: “Often, the EGR valve becomes clogged with carbon deposits (a mixture of iron oxides that crystallize on the iron parts). In order to restore your clogged EGR valve to proper functioning, a good cleaning may be sufficient. This will extend the life of your EGR valve. There is an effective way to clean it: driving at high speed. By driving a few kilometers at higher speeds with a lower gear than normally used (for example, driving at 110 km/h in 4th gear instead of 5th), you can burn off the carbon deposits in your EGR valve and thus clean it. If descaling is possible, you can also clean your car’s EGR valve yourself with various EGR valve cleaners available at Oscaro.com. These cleaning products are usually sold in aerosol cans and are sometimes accompanied by a cleaning solution (in kits).
When replacement is the only solution, the cost of this operation can be around €350.
