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.