The need for EGR cooler replacement on diesel engines is an issue we see frequently. In 2002 government emissions requirements for diesel engines required manufacturers to adopt this technology that had been around in cars for years.
The idea behind exhaust gas recycling (EGR) is to cut NOx emissions by recycling exhaust gas through the intake system. Since there is unburned fuel in the exhaust stream, this gives the engine another chance to burn this fuel and lower the combustion chamber temperature.
When you burn fuel in the presence of nitrogen (N2, 78% of our atmosphere), you create oxides of nitrogen (NOx). The cooler the combustion chamber, the less NOx we make. NO2 is the substance we associate with the harmful effects of smog, such as trouble breathing and itchy eyes.
The EGR cooler is placed in the exhaust stream, following the exhaust manifold. Also flowing through the EGR cooler is engine coolant. Since the coolant is colder than the exhaust gas, heat flows out of the exhaust stream. Cooled exhaust gas is routed to the EGR valve and into the intake system.
EGR coolers are susceptible to several problems. Carbon from the exhaust stream can clog the flow of exhaust gasses through the EGR cooler and the EGR valve downstream of the cooler. Coolant flow through the EGR cooler can also be obstructed if contaminated coolant is not replaced on schedule. Over time, EGR coolers will develop leaks.
Symptoms of these issues include:
White exhaust smoke means the coolant is burned because of a leak in the EGR cooler between the coolant and exhaust gas heat exchanger passages. Besides white exhaust smoke, you will also notice decreasing coolant levels. When parked, coolant puddles on the ground may also indicate a leaking EGR cooler.
A leak allowing coolant into the exhaust flow will go to the EGR valve, gumming it up and causing the system to be inoperative.
A bad EGR cooler should cause events illuminating the Check Engine light and triggering a code.
The EGR cooler provides cooler running temperatures and can lengthen the life of engine components. A bad EGR cooler will cause damage to your engine and turbocharger problems. You cannot pass a smog check with a Check Engine light on.
We recommend bringing your vehicle in for a diagnosis as soon as you notice these symptoms for the long-term health of your expensive engine. At Fremont Foreign Auto, we have state-licensed and ASE-certified diesel technicians who perform these procedures frequently. Call us or visit our website to get a quote and book an appointment for any diesel repair you need.
