The EGR Valve or Exhaust Gas Recirculation Valve to give it its full name is used to control emissions. The valve sends exhaust gas back into the intake manifold. This is then sucked into the combustion chamber so it can reduce the temperature to stop the formation of nitrogen oxides. Nitrogen oxides are one of the worst pollutants produced by a combustion engine. It also helps to reduce engine knocking.
The EGR Valves are fitted to petrol & diesel engines. They are more critical in diesel engines as the combustion temperature is higher. A downside of this is more carbon particulates are formed and need to be filtered out before the exhaust gas is released into the environment. This is where the DPF or Diesel Particulate Filter comes in. It filters out the carbon particulates while the EGR Valve reduces nitrogen oxides.
Popular Questions Asked
What are the symptoms of a failing EGR valve?
Symptoms can be:
- The engine performance drops off and stalling or rough idling
- Poor acceleration and knocking noises from the engine
- The engine management light may be on
- You can smell unburnt fuel
- Fuel economy will decrease
Is it better to clean or replace EGR valve?
Depends on how bad and how old it is. If around 8 to 10 years old or very dirty definitely replace it. There are cleaning solutions you can get to remove the carbon deposits.
How do you prevent EGR valve failure?
The best way to prevent it is regularly maintenance your vehicle. I quick blast down a freeway with lots of acceleration and deacceleration is good for it rather than driving sedately around town.