Symptoms of Bad EGR Cooler for Heavy Duty Applications

Symptoms of Bad EGR Cooler for Heavy Duty Applications

Exhaust Gas Recirculation Coolers or EGR Coolers are devices that cool the exhaust gases, and work in conjunction with the SCR to reduce nitrogen oxide emissions (NOx) for heavy duty internal combustion engines. The purpose of an EGR cooler is to facilitate the reduction of emissions and meet current emissions standards set by the US Environmental Protection Agency. But what happens if your EGR cooler begins to fail? What are some of the indicators of a failing EGR cooler?

There are three 3 major symptoms of a leaking EGR cooler:

  1. White smoke. When an EGR cooler starts to fail, it transfers coolant out of the EGR cooler into your exhaust system. When this happens, the exhaust interacts with that coolant and turns it into steam. This "white smoke" is released through your exhaust system of your heavy-duty engine and is a sure sign of an EGR failure.

  1. Missing coolant from your D gas/overflow bottle. When your D gas/overflow bottle is missing coolant, but you do not see any indication of an external leak (i.e., dripping underneath the vehicle)-it is a strong indication that your EGR cooler is leaking internally. As a result, it drains the coolant in your exhaust system which creates the possibility of engine overheating or in this case, "white smoke."

  1. Slimy EGR valve. The most efficient way to determine if your EGR is failing is to physically look at it. If you remove the valve, which is located near the top of the engine next to the oil filter, it should be full of a dry black charcoal carbon (soot) which is from the exhaust system. If you have a failing EGR cooler, the dry carbon would be replaced by a black slime - like substance. The is caused by the hot coolant interacting with the hot exhaust and steam clogging your EGR valve.

If you have ANY of these three symptoms, it is a strong indicator that you have a failing EGR cooler.