The EGR valve has been controversial since its creation… But how does it work? Why does it get clogged? And how can it be cleaned? Opting for its removal is not always a good idea when a complete cleaning of the EGR valve can be performed!
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What is the purpose of the EGR valve?
The EGR valve (Exhaust Gas Recirculation) is a system designed to eliminate toxic gas particles produced by an engine. These are nitrogen oxides (NOx) emitted from the exhaust gases of combustion engines.
As these emissions are harmful to health and the environment, the European Union has imposed a maximum emission rate since 2000 for vehicles in production. This limit has been set at 80 mg/km since 2015 (Euro 6 standard), compared to 180 mg/km in 2009.
Note that the particulate filter (DPF) only appeared later on Diesel vehicles to comply with increasingly stringent EURO standards.
How does the valve work?
The operating principle of the EGR valve is quite simple. It involves a process of cooling exhaust gases by recirculating them into the intake manifold to burn them a second time, thereby reducing nitrogen oxide particles as much as possible.
The EGR valve operates when the engine runs at low speed.
Clogged EGR valve
Why clean your EGR valve?
The operation of the EGR valve is quite controversial. Recirculating the gas inevitably leads to particle deposits in the intake and the valve, resulting in the formation of a black layer (soot) that can cause various engine problems and failures = the EGR valve gets clogged.
This is very common, especially in urban areas where low-speed driving due to traffic lights, slowdowns, and traffic jams is prevalent.
This soot build-up can prevent the valve from opening and closing.
If it remains closed, it becomes completely inactive. The vehicle will continue to function normally but will pollute heavily. However, if it stays stuck in the open position, the engine will suffer even more from intake clogging, and the injectors may get blocked.
This is why cleaning your EGR valve is important!
Is my EGR valve clogged?
Don't panic! First, your engine may behave abnormally:
- Loss of power during acceleration
- Frequent stalling at low speed
- Black smoke coming out of the exhaust pipe
Additionally, your anti-pollution light or engine warning light may be on. This could indicate a malfunction of the EGR valve.
This is a reason for a failed technical inspection due to pollution!
An automotive diagnostic via your vehicle's OBD port will provide a more precise answer by returning a fault code corresponding to a specific issue. As shown below, the fault code indicates a problem with the EGR system.
Cleaning the EGR valve
If you notice that your EGR valve is clogged, several solutions are available depending on the condition of your valve.
Cleaning your EGR valve is the simplest way to remove the soot. A cleaning approximately every 20,000 kilometres with a high-speed drive on the motorway for about ten minutes (burns off the clogged particles) is sufficient to properly maintain your valve and avoid having to replace it due to excessive clogging.
Cleaning your EGR valve is not necessarily complicated, especially if you have an automotive diagnostic tool to assist you!
However, if it is in very poor condition, it is better to replace it to avoid significant damage to the engine and injectors in particular.
The price of an EGR valve varies greatly depending on the brand and engine type of the vehicle but generally ranges between €250 and €600 including VAT.
So, remember to clean it regularly to ensure a longer lifespan.
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Removing the EGR valve
The last, somewhat extreme solution: opting for the removal of the EGR valve.
Some motorists indeed choose this by locking the flap in the closed position so that the valve becomes inactive. The vehicle then pollutes heavily and does not comply with the European Union's environmental standards!
Moreover, the engine may start to operate in "degraded mode", causing impaired vehicle performance, including significant power loss.
We strongly advise against this solution!
Instead, we recommend cleaning the EGR valve regularly to prevent excessive clogging. With an OBD scanner and by following our recommendations, cleaning your EGR valve is not that complicated!