Symptoms of a Bad EGR Valve & How Much It Costs to Replace

One such part would be the Exhaust Gas Recirculation (EGR) valve. Many people may not even know that such a part exists so in this article we will give it the spotlight for once. We are going to focus on the signs that this part may need replacing and most importantly how much that might cost.

What Does the EGR Valve Do?

With a name like exhaust gas recirculation valve you probably do not need too deep an explanation because it's essentially there in front of your eyes. So yes, the EGR recirculates the exhaust gases, but why and what are the benefits?

The EGR takes a specific amount of exhaust gases and recirculates them back into the combustion chambers. This may seem odd but there is in fact a purpose to this. Firstly it will optimize the fuel to air ratio without requiring extra air from outside the engine.

This part really comes into its own by recirculating the exhaust gases into the chambers where the chemical makeup of these fumes helps to actually cool them. You must remember that several times a second a combustion event is happening in these chambers so it gets hot fast.

When you cool the combustion chambers you help decrease harmful exhaust fumes and actually boost the engine's performance. These recirculated gases can drop the chamber temperature by up to 302 degrees Fahrenheit.

The operation of this part is controlled using sensors which tell it when to open and close in order to maximize engine performance. If one of these sensors fails then the valve will not get the right messages or if the valve gets stuck then the system does not work correctly.

Where Is the EGR Valve?

As you might imagine the EGR valve will be located in a pipe that runs to your exhaust and this will usually exit the engine near the top. It may take a little searching to find but if you know what you are looking for it should not be too difficult.

Although it is often near the top of the engine sometimes this valve may also be deeper down and harder to find. The pipe it is connected to should still originate at the top of the engine so if you find the right one you just have to follow it down.

It should be noted however that in some vehicles the pipes are integrated into the cylinder head so this can make locating it a little more difficult.

Signs of a Bad EGR Valve

There are a few notable symptoms of a bad EGR valve that might give you a clue that this part may need replacement. We should note however that most of these symptoms may also indicate other issues as well so you will likely have to do extra digging to confirm.

Engine Knock

Engine knock is an audible sound that occurs when cylinders misfire. It is most noticeable while idling and is not a good sound to hear. A misfiring engine is essentially slowly destroying itself so this is something that needs to be fixed.

The EGR valve by decreasing combustion chamber temperatures actually reduces misfires caused by an overheated cylinder setting off combustion early. If the EGR valve is not recirculating the gases then the chambers are not being cooled and you can get misfires.

Engine knock combined with a check engine light may indicate an EGR issue which you should fix very quickly.

Check Engine Light

The check engine light covers a lot of engine issues so it may indicate literally hundreds of potential faults. One of them may be the EGR valve but the only true way to know would be to hook up an OBD2 scanner tool and read the trouble codes saved in the car's computer.

These trouble codes can let you know what instigated them as long as you have a list of codes for your specific model. You can usually locate this in your user manual but it may also be available for free online.

Increased Emissions

This is a little hard to spot with the naked eye because often emissions are not particularly visible unless you have a real problem. There will be an increase in emissions if the EGR valve fails however so this is something that can be measured.

If you have to undergo an emissions test to have your car registered you might find that your car fails if the EGR valve is not working. You may see a slight increase in smoke from the tailpipe but this is not a common symptom so may not even be worth trying to look for.

Improved Fuel Economy

This is one of those rare cases in which improved fuel economy is not a good thing at all. If the EGR valve is not allowing recirculation of the exhaust then the chambers instead will use air from the intake. This can lead to a lean air/fuel mix and obviously less fuel being used.

You might imagine that using less fuel can not be bad but if the combustion has too low a fuel content it can actually be harmful to the engine. If you leave this issue unrectified then over time engine damage becomes much worse and can cost you big in repairs.

Reduced Engine Power

As mentioned the EGR valve when operating helps your engine's performance. You can well imagine then that when it is not working your performance drops which also leads to a drop in engine power. This will affect your top speed and slow down your acceleration.

The problem is most noticeable at low speeds if the valve is stuck open or at high speeds if the valve is stuck shut.

Rough Idling

This is another good sign of a potential EGR valve issue and it is connected to the engine misfires that a failing valve can cause. When you are idling your engine is at its most sensitive so you can often feel the vibration from the misfires and hear the knocking sounds.

This issue happens mostly when the valve is stuck open and you have just started the car. If the valve is stuck closed the issue will develop more as the engine warms up so it may start while idling at lights.

How Much Does It Cost to Replace the EGR Valve?

Replacement of the valve may be needed however sometimes it only needs to be cleaned. This can be done with a carb cleaner and a wire brush. You would simply remove any clogs of debris that has built up.

If a clean isn’t going to fix the issue then you will have to replace the part and this is not at all cheap, A new part can be between $150 - $400 with labor costs ranging from $75 - $400. This means that overall you can be paying $225 - $800 to get the part replaced by a mechanic.

If you can perform the work yourself you could save a fair amount of money. Thankfully if the part is easy to access it is not a complicated replacement. If there is a more difficult placement there may be more work involved.

Conclusion

The EGR valve is very important to our engines and if it is not working we could potentially be looking at a building issue with the engine as a whole. It can be an easy fix if you have the skills but the parts are not cheap.

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