Cinzas 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 lower the combustion temperature and reduce the formation of nitrogen oxides. It is present 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 electric/electronic control in newer engines), which remains open when the engine is operating under 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 and not compromise engine performance. Black smoke coming from the exhaust may indicate an open position, as excessive use of the valve leads to particle and soot overproduction. 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: «The EGR valve is often clogged with carbon deposits (a mixture of iron oxides that crystallize on the iron parts). In order to restore proper functioning to your clogged EGR valve, a good cleaning may be sufficient. This will prolong the life of your EGR valve. There is an effective way to clean it: drive at high speeds. Driving a few kilometers at higher speeds with a lower gear than usual (for example, driving at 110 km/h in 4th gear instead of 5th) can burn off the carbon deposits in your EGR valve and thus clean it. If decalcification 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.
