What is an EGR Cooler?

What is an EGR Cooler?

The Exhaust Gas Recirculation system is one of the methods used to reduce the amount of harmful emissions from the engine. It is an important part of your engine system, and like all heavy-duty components, it must operate in an extremely tough environment.

But why do the exhaust gases running through this system need to be cooled? How do you know the cooler in your engine is going bad? Why does it need to be cleaned? Can You prevent your EGR cooler from failing? Continue reading for answers to these questions and more, to ensure the longevity of your EGR cooler and protect your engine.

What does an EGR cooler do?

Pollutants come in more form than just unburnt gases from your engine. They also form when extreme heat inside your diesel's combustion chamber breaks chemical bonds, forming new molecules. Nitrous Oxides (NOx) and ozone (O3) are formed when this heat combines nitrogen and oxygen atoms from the air. NOx can form smog, and when it mixes with water, it can form acid rain. The ozone layer helps protect us from UV light, but at ground level, this gas may cause breathing problems, especially for those with sensitive lungs/ respiratory issues.

Exhaust Gas Recirculation (EGR) lowers combustion temperatures by diluting the air/fuel mixture with a small amount of inert exhaust gas. The performance of your engine remains high, while the opportunity for pollutant formations is decreased significantly. The most effective diluting of the air /gas mixture happens when the exhaust gas is cool, hence the existence of the EGR cooler.

The EGR cooler is a water to air heat exchanger that sits between the turbo and the EGR valve. The body has a hollow tube or series of tubes for the hot exhaust gas to pass through. Surrounding these tubes, are several coolant passages. Heat is transferred through the walls separating the exhaust and coolant, delivering cooler, inert exhaust gases ready to able to lower peak combustion temperatures. The flow of exhaust gases through the EGR cooler is controlled by the vehicle's computer via the EGR valve.

The heat from the exhaust system is transferred to the vehicle's cooling system.  This additional heat is simply dissipated through the radiator.  However, since the EGR cooler connects the exhaust and cooling systems of your engine, failures inside the cooler may lead to coolant loss, overheating, and engine damage, among other failures.

What happens if your EGR cooler fails?

If an EGR Cooler fails, it is bad. Typically, there will be a crack or a leak between the coolant and the exhaust side of the cooler. That will often mean coolant will enter the exhaust gas pathway on its way back into the engine. In a sense, it is pouring water into the engine. A typical first symptom is a lot of white smoke from your exhaust as the coolant becomes steam out the exhaust stack. You may also notice repeated low coolant, or coolant overflowing, as the coolant is pulled into the exhaust path or exhaust is pushed into the coolant path. Since diesel is a constant volume machine, the steam introduced will cause whatever the weak link in your specific engine to fail. Catastrophic severe damage to the engine can occur as the coolant is boiled in the combustion chamber, severely overstressing internal engine components.

Why are AMBAC EGR Coolers Better?

With a 110-year history in the industry, we have seen our fair share of design flaws. And typically, EGR coolers are no different. The OEM design is flawed; the material is too fine, and the holes are too small (like the cross section of a radiator). When they plug with soot (the exhaust gasses go through it), they overheat. This causes the silver solder to melt and the cooler to come apart, allowing the coolant to mix with the exhaust. This can cause problems ranging from turbo failures to blown head gaskets and broken head bolts to connecting rods and pistons.

Our EGR Coolers combat this issue by being redesigned with larger diameter, thicker wall tubes that are made of 303 stainless steel. They are then welded together not silver soldered, ensuring that the cooler will not come apart.