How do I know if my EGR cooler is failing?

Your complete guide to EGR cooler failure

Your Exhaust Gas Recirculation (EGR) system is vital in reducing emissions, but it can also regulate internal engine air temperature. This prevents engine overheating, so it’s important to maintain. Symptoms of EGR cooler failure can include odd-looking exhaust emissions and engine overheating.

These systems are commonly fitted on modern diesel engines and some gasoline engines. As diesel fuel produces more environmentally damaging emissions than petrol, EGR systems are important for effective pollution control. But what occurs when an EGR cooler fails?

Some EGR cooler failures can lead to severe engine damage and possible impairment to other components. It can also go unnoticed for some time, as failure symptoms are not always obvious.

Natrad has a range of quality EGR coolers suited for a wide variety of vehicles. For the right replacement, get in touch with your nearest cooling specialist today.

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How do I know if my EGR cooler is bad?

There are four key signs of a bad EGR cooler.

  • White steam or smoke at the exhaust
  • Lowered coolant level with no visible leaks
  • External coolant leakage
  • Check engine light

If you notice any of these four symptoms, getting your vehicle checked out right away is a good idea. It might only be the case that your EGR cooler needs cleaning, but there is a possibility that something more serious could be involved.

1. White steam or smoke at the exhaust

This may be tricky to view yourself, so it is a good idea to ask a passenger or a friend to check this for you. White steam or smoke can be a sign that the EGR cooler has leaked internally and that coolant has been introduced into the intake system. The coolant entering the combustion chamber is boiled and expelled as a gas, which is unsuitable for your cooling system. It may not cause any direct damage to the exhaust system, but your lowered coolant level can eventually lead to your engine overheating.

2. Lowered coolant level with no leaks

As mentioned above, losing coolant means less coolant flowing in your cooling system. Without enough coolant, air pockets can arise, leading to ineffective cooling. There might be no visible signs of leakage, but lowered coolant levels can indicate an internal problem with the EGR cooler.

3. External coolant leakage

If your EGR cooler has developed a leak, it may drip under the car or build up around the leakage point, leaving a dried coolant residue. This is easier to diagnose as it is often visible. Keep an eye out for low coolant levels or visible leakage, especially if the identified leakage is the same colour as the coolant in your radiator.

4. Check engine light

Often, a vehicle’s Engine Control Unit (ECU) will tell that there is a discrepancy in the system and register a fault code. This will turn on the check engine light. It may turn on when the EGR cooler becomes restricted or isn’t functioning properly. Either way, when you see the check engine light it means it’s probably time to check your engine components.

What are the reasons my EGR cooler has failed?

EGR coolers can fail for a few different reasons. Some are treatable, but more often than not the EGR cooler will need to be replaced.

Possible failures include:

  1. Blockage Sometimes, the coolant passageways in the EGR cooler become clogged and prevent effective exhaust gas cooling. This is hard to tell without removing the EGR cooler and checking. However, overheating or increased fuel consumption might be symptoms of a blockage.
  2. Corrosion — Some EGR coolers may be susceptible to corrosion, depending on the application. This may be due to build-up from particulates or acidic condensation at low temperatures.
  3. Thermal stress — EGR coolers can exhibit cracking or warping due to repeated cycling of extreme temperatures. The cooler is subjected to exhaust gas that can reach 800°C, which is rapidly cooled to around 200°C. Over time, this can damage the EGR cooler and cause leaks or complete failure.

What to do if your EGR cooler is failing?

If you suspect your EGR cooler is failing, taking immediate action is essential to prevent further issues. The EGR system reduces harmful emissions by recirculating exhaust gases into the combustion chamber. But when the EGR cooler malfunctions, it can result in hot exhaust gas entering the cylinders, potentially causing engine damage and increased emissions. To address this, check the EGR valve and the cooling components.

If you confirm a failure, consider repairing or replacing your EGR cooler to maintain the exhaust gas recirculation system and to ensure your vehicle operates efficiently while minimising emissions.

Natrad technicians can diagnose EGR cooler failure and prescribe the best solution for your vehicle. We also have a range of aftermarket EGR coolers for all types of vehicles.


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