Australian 4WD Action – August 2019

You’ve probably heard about

EGR systems that choke up with

carbon. So what are they, and

how do you stop it?

WHAT EXACTLY IS

AN EGR SYSTEM?

“Exhaust Gas Recirculation

(EGR) is a process devised to

reduce a certain pollutant

produced in the combustion of

diesel fuel; the pollutant is

Nitrous Oxides (NOx),” says

Andrew from Diesel Care.

“Manufacturers found that

recycling some exhaust gases

via a pipe into the air intake

system, the result is

that combustion

temperature is

lowered, and the result

of this is less NOx is

produced.”

WHAT FAILS

AND HOW DO

YOU FIX IT?

“When an EGR system

is working properly on

a healthy engine, the

performance should

not be greatly

affected,” Andrew

continues. “However,

problems arise when

it’s not working

properly. Exhaust gases are

recycled at certain engine load

conditions and to control the

flow a valve is needed. The EGR

valve opens and closes at

certain times by means of a

vacuum servo or stepper

motor. It’s important that the

Valve, and the components that

control it, are operating

correctly. Opening at the wrong

time, like when the engine is

under load, would have a major

effect on performance. If an

EGR valve becomes sticky from

carbon deposits it may not

close properly, or seal

completely. This will have a

significant effect on

performance and how well the

engine runs. Faulty EGR

hardware is replaced, but the

cleaning out of the black gunk

in a badly effected engine has

two forms in our shops; heavily

clogged intake manifolds have

to be removed for cleaning,”

Andrew says. “This is time

consuming and expensive. If

the deposits are moderate or

less we use an on vehicle

solution that chemically

loosens up the deposits and

burns them in the combustion

process.”

ENGINE CATCH

CANS – THE

ESSENTIAL

SAFEGUARD

“The gunk deposits form when

the hot exhaust fumes mix with

crankcase fumes,” says

Andrew. “So if one half of the

recipe can be taken away the

other is ... less harmful.

Stopping the flow of exhaust

gases is firstly, Illegal and

secondly, usually causes the

diagnosis system to bring a

warning light on. So, the easier

choice is to stop the oil from

joining the party by catching it

before it gets into the manifold.

Hence the term catch can.

Installing a catch can to

remove oil mist is a good

preventative measure in

reducing EGR side effects.”

Is your modern diesel feeling a bit sluggish lately? The cause may not be what you think

ALL CHOKED UP

STEP^2

This is^ why^ catch^ cans^ are^ so^ vital^

• just^ check^ out^ how^ carboned^ up^
  this^ vehicle’s^ inlet^ manifold^ was

Check this out – inlet plumbing on

a vehicle with barely 100,000km

that hasn’t run a catch can

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