EGR Cooler – Everything you need to know

Imagine taking your car in for a service after experiencing some difficulties, and the mechanic tells you that your car has suffered “EGR cooler failure”. If you heard that, would you know exactly what the mechanic was talking about? Do you know what the EGR cooler does? Do you know what EGR means? If not, then today’s blog must be of great help to you.

What does EGR mean?

Exhaust gas recirculation coolers (known more often as simply EGR coolers) are special devices that help reduce harmful NOx (nitrogen oxide) emissions in internal combustion engines. In the modern context of increasingly strict rules emissions regulations, they are a more important component than ever, especially in diesel engines.

What does an EGR cooler do? How it works?

The EGR cooler works to actively reduce emissions levels by first diluting the air/fuel mixture in your engine using inert exhaust gas. These inert gases have very little impact on engine performance, but at the same time drastically reduce the chances of harmful exhaust gases being produced in the first place.

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The EGR cooler sits between the turbo and the EGR valve, its body is a hollow tube (or several tubes) along with several passages for coolant. The heat comes in through the walls, which separate the exhaust and the coolant, which brings the exhaust gases into the mix and lowers the peak combustion temperature. The EGR valve controls the flow, the valve itself being managed by the vehicle’s on-board computer.

What causes the EGR cooler to fail? What are the symptoms?

The main cause of EGR cooler failure is internal cracks. The good news is that there are no moving parts in the component, which means that other more complex wear and tear does not happen like with a turbo or its transmission. However, the persistent cycle of cooling and heating eventually takes its toll, creating fatigue in the material and eventually creating cracks and small fractures.

EGR fault symptoms

Drop in Coolant Levels

If you notice that there is coolant in the overflow bottle or that your engine is consuming coolant, it’s a classic sign that your EGR cooler has broken down. Cracks cause the coolant to start leaking and mix with the exhaust stream.

White smoke

Check (or ask a friend for help) to see if you can see white smoke coming out of the exhaust. If you can see white smoke, it is most likely caused by a coolant leak entering the exhaust stream, burning and then vaporizing, creating the white hue you see in the smoke.

EGR cooler

Inspection reveals damage

Locate the EGR valve and remove it. If you notice that it is wet, or appears to be steam cleaned, or that it has become glued together, these are all possible results of problems within the EGR cooler itself.

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Can you clean the EGR cooler? As?

Replacing the EGR cooler is a complicated and therefore often expensive job for a professional mechanic. Therefore, replacing the EGR valve is best left as a measure of last resort. The first thing you should try to do is clean it up.

To be clear, cleaning the EGR cooler will not fix fractures or cracks. Cleaning your EGR cooler should be viewed as a preventative measure that can help extend its life and save you spending the money to replace it. The following is a quick step-by-step guide to cleaning:

Step 1: Power Off, Open Hood, Locate

The first steps are to ensure the vehicle is turned off and the engine is cold. Open the hood and first locate the air intake hose and intake manifold hose. Both need to be removed. You will most likely find them on the side of the engine.

Step 2: Disconnect

Next, you need to disconnect the PVS heating element, and then the intake manifold switching valve. These are held in place by hex head screws.

Step 3: Remove

With the bolts and shift valve out, you can remove the vacuum lines from the EGR and anti-shudder valve, along with the hex bolt and clamp that hold the turbo intake manifold in place. The EGR itself is likely screwed in, so you’ll need to remove it.

Step 4: Spray and Cover

Now that you have access to the EGR, you can start the cleaning steps. Firstly, spray hot water into the inner cavity of the EGR for about 10 minutes in total. Then use a rubber plug to block the EGR cooler outlet.

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Step 5: Mix and Fill

Mix the EGR system cleaning fluid according to the manufacturer’s instructions on the container. Typically this is about 4 parts hot water and 1 part cleaning fluid. Fill the EGR with the cleaning solution.

Step 6: Wait

After filling, wait an hour to let the solution soak in and do its job.

Step 7: Drain, Rinse, Dry and Restore

Remove the plug to allow the EGR to drain, ensuring you are not breaking any local rules by allowing it to leak into the wrong drains. Rinse the EGR again with hot water and then dry it. Put everything back as it was before you started and voila!

egr cooler clean

What Is Involved in EGR Cooler Replacement? How much does it cost?

Fully disconnecting the EGR involves a much more extensive process, including disconnecting the battery cables, draining the coolant from the radiator, and carefully removing everything before restoring it with a new component. The job typically takes 2-3 hours to complete and will end up costing around $300 on the lower end of the spectrum.

If you’re replacing the EGR on a high-spec car, it could cost up to $3,000 to get the job done. That’s why cleaning is the best alternative, if possible, to extend the life of the unit and postpone replacement longer. When used correctly and when properly cleaned it should last 80,000 miles and possibly more.

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