A combustion chamber can reach greater than 1300 degrees F when your engine is at operating temperature, and that is a recipe for mechanical failures and increased emissions.
Your engine has an EGR, or exhaust gas recirculation valve, to help with the extreme heat when your engine is running.
But EGR valves are not without their faults, even though they last about 10 years without a glitch. If they fail, you’ll notice a number of symptoms that will suggest it’s time to find a replacement.
Costs are going to vary quite a bit depending on your vehicle you own, as some are available for less than $50. While many are considerably higher, the average cost is somewhere around $90 with additional charges for labor and incidental parts.
What does an EGR value do? What are the symptoms of a bad EGR valve? Learn that and what causes them to fail, and if there is any way to prevent it.
What Is an EGR Valve and What Is Its Function?
The ignition and combustion process of an engine requires a reasonably precise air-fuel mix to create power for the pistons. However, this process creates a great deal of heat and harmful nitrogen oxide (NOx) emissions.
The EGR Valve redirects some of the exhaust back into the combustion chambers to lower your car’s NOx emissions.
This is how it works:
The EGR valve operates in two main settings:
- Closed – When the engine first starts,
- Open – When the engine is idling or running at low speeds.
When the engine receives a partial load signal, such as when the engine is idling, the Engine Control Module (ECM) tells the EGR valve to open, allowing the exhaust to mix with the fresh air and fuel in the intake manifold before entering the combustion chamber.
Now, when the exhaust is drawn back into the combustion chamber, it is already spent fuel gases and does not burn like a fresh air-fuel mix.
There is a lower concentration of oxygen in exhaust gases, which naturally lowers the peak combustion temperature, and therefore, NOx is formed at high temperatures when you have combustion. Adding inert exhaust gases helps to lower NOx emissions.
Wondering how to spot a failed EGR valve? Let’s find out.
Bad EGR Valve Signs
Here are 8 common signs that an EGR valve has failed:
#1. Rough Engine Idle.
If the EGR valve is stuck in the open position, more exhaust gas than normal will flow back into the combustion chamber. This interferes with the intake of fresh air, such that the proper air-fuel mixture does not happen.
This can cause the A/F mixture to be too rich in exhaust gases (displacing atmospheric air), and that can further impair the combustion mixture. The net result is a rough idle for the engine.
#2. Check Engine Light.
The Engine Control Module (ECM) controls all of the functions and operations of the EGR valve, which includes whether the Check Engine Light comes on.
If your vehicle is showing one or more symptoms (like those mentioned above), and the Check Engine light is illuminated, it can indicate an EGR valve defect. If the ECM diagnoses that the air/fuel mixture is not correct in the combustion chamber or that the EGR valve cannot move freely to the commanded position, it will set a Diagnostic Trouble Code (DTC).
Common Diagnostic Trouble Codes (DTCs) associated with a failed EGR valve include P0300, P0100, P0101, P0102, and/or P0104.
#3. Stalling.
If an EGR valve fails in the open position, it is likely to cause engine stalling at idle.
This is because too much unmetered exhaust gases will enter the intake tract, which produces a large vacuum leak!
#4. Starting Problems.
You will also notice that your car may be becoming more difficult to start if the EGR valve has failed in the open position. This will happen for similar reasons as before.
The exhaust gas recirculation occurring during low temperatures and at start-up can make an engine unable to run normally.
#5. Engine Knocking or Pinging Sounds.
If the EGR valve gets stuck in the closed position, then exhaust gases cannot recirculate. If the exhaust gases cannot recirculate, heat continues to build in the combustion chamber until it finally exceeds the combustion temperature threshold.
The only logical outcome of this would be that fuel combusts earlier than it should normally. This is especially true at low RPMs, which correlates with sounds that you may hear coming from the engine, such as knocking or pinging sounds.
By the way, knocking or pinging sounds could also damage other components, like spark plugs, so pay attention to this.
#6. Increased Fuel Consumption.
The EGR valve opens and closes depending on throttle movement and vacuum in the exhaust manifold. If there is carbon buildup in the EGR valve, it could get stuck in the open position, which means exhaust gas may re-enter the combustion chamber at the wrong time.
This could also cause vacuum-operated EGR systems to have a vacuum leak, and subsequently, the vehicle’s economy might be affected negatively through fuel economy as the engine would attempt to make up for the lost vacuum by injecting more fuel.
#7. The Smell of Fuel.
Even when an engine is operating properly, tailpipe NOx emissions have a nasty, lingering odor that should not be inhaled. A faulty EGR valve could lead the engine to consume more fuel.
This naturally means that more NOx and unburned hydrocarbon fuel would be emitted through the engine and tailpipe system, and that is what you would smell, even if it is at the rear of the vehicle or possibly in the cabin.
#8. Excessive Emissions.
There can be several reasons a vehicle fails an emissions test, such as dirty air filters, loose gas caps, or even malfunctioning fuel injectors or oxygen sensors. A faulty EGR valve is simply another issue to consider.
At the heart of EGR valve designs is the idea of emissions reduction. A malfunctioning EGR valve is very likely to compound vehicle emissions, and therefore, a vehicle is less likely to be successful in an emissions test or diagnostic.
Reasons for EGR Valve Failure
Bad Fuel
Poor quality or contaminated fuel can cause contaminants to build up in the EGR valve. Impurities in fuel can create deposits inside the valve, decreasing the possibility of the valve opening and closing correctly.
This can lead to decreased performance, increased emissions, and possible damage to the EGR valve.
Neglect to Maintain Regularly
Lack of vehicle maintenance, which neglects to maintain the vehicle regularly, is a contributing factor to EGR valve failure.
Carbon build-up in the EGR valve and surrounding EGR valve components can impede the flow of exhaust gas and significantly impair the operation of the EGR valve.
Faulty Parts
A faulty EGR valve may also be caused by ineffective or damaged parts around the EGR valve. The EGR solenoid, vacuum hoses, and electrical connections can all have a negative impact on the EGR valve.
A faulty EGR solenoid will fail to open or close accordingly, and damaged vacuum hoses or electrical connectors will stop the EGR valve and ECM from communicating with each other.
Manufacturing Defect
Although rare, some EGR valves fail because they have a manufacturing defect. This may lead to poor performance or premature failure even when the EGR valve is working properly.
Extreme Operating Conditions
Extreme operating conditions may include heat, heavy dust, and heavy loads for long periods of time, and can lead to an EGR valve failing.
Extreme operating conditions can lead to increased carbon build-up and stress placed on the components, which may lead to premature component failure.
EGR Valve Replacement Cost
The average EGR Valve Replacement cost is between $387 and $470. The cost of labor is between $95 and $120. The price of the parts is between $293 and $351.
This estimate excludes taxes and fees, and does not apply to your specific location. Also, related repairs may be necessary.
The exact price of EGR valve replacement generally varies from vehicle to vehicle, as a result of differences in parts prices and labor charges.
Some of this variation in cost can be diminished if you choose to perform the labor required for this process as a DIY service.
Generally speaking, you can expect to pay anywhere from $150-$550 to replace the EGR valve in your car, with parts costing in the range of $100-$450.
Keep in mind that there are some outliers that are well beyond this price range. Often, these are foreign makes and performance cars.
Can You Drive with a Broken EGR Valve?
In some cases, yes, it is possible to drive with a faulty EGR valve, but don’t.
In other cases, a vehicle may simply not operate with a failing EGR valve due to the severity of the driveability-related symptoms that are incurred. The subtext is the way the EGR valve has failed.
If the EGR valve has failed in the open position, the performance of the vehicle will most likely be erratic, and intermittent stalling/no-start conditions could be present. The reason is that a stuck open EGR valve may act as or cause a substantial vacuum leak, allowing unmetered air into the cylinder head.
Conversely, a vehicle with a stuck closed EGR valve could run with little issue and possibly no secondary symptoms, not that this is entirely without risk.
In any case, always address the issue of EGR failure as soon as possible. Addressing the issue quickly with evaluation and repairs will help keep the engine running as designed and may help avoid hence avoiding any unexpected failures. If you do not feel comfortable performing such repairs, then have it evaluated at a reputable service center.
What is an EGR delete? Should you get one?
An EGR delete is a process in which the EGR valve of a vehicle is removed, followed by plating off the flange where the valve originally was. Eliminating an EGR valve means that exhaust gases no longer recirculate through an engine’s intake manifold.
Advocates of an EGR delete say that they benefit from fuel and/or engine performance, smoother engine idle, and a more reliable engine.
However, it’s also essential to realize that there are a number of downsides to getting an EGR delete as well. For example, getting an EGR delete will likely make it impossible to pass state-mandated emissions testing.
Additionally, removing any emissions compliance device that is put in place by the factory can also create legal and/or warranty issues.