Dirty fuel problems
Date: 25.06.2012
Be aware what a bad batch of fuel can do to your car.
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Contaminated fuel can have bad consequences for your tow vehicle.
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DO YOU EVER think about the fuel you are putting in your
tank? Beyond worrying about how much it costs and which grade of
fuel to buy, probably not. But you should. A bad batch of fuel can
wreak havoc on both diesel and petrol engines. So let's have a
closer look the how, where and why of fuel contamination.
Fuel quality in Australia is generally not as good as the rest of
the world and the main contaminants are water, algae and sediment
from the bottom of the tanks at the service station.
Contamination is a consequence of poor management and unfortunately
there isn't much we can do to prevent us from filling up our next
tank with contaminated fuel. In every litre of fuel there is always
a nominal amount of water; the Australian fuel standard
determination is 0.05% by volume. This amount of water is said not
to impact fuel system operation and makes its way into the fuel via
condensation in the tank and by accidental ingress when tanks are
filled.
Air and water borne spores can also contaminate fuel. Different
types of spores require different conditions to germinate and they
will only germinate in the right conditions. The spores settle on
the surface of the fuel where they remain dormant. Movement of the
tank washes condensation off the sides of the tank, mixing spores
into the fuel in the process. Dissolved oxygen in the water acts as
a trigger for germination and heat accelerates the process. In
warmer climates such as the outback, more rapid spore growth is
experienced because of the higher temperature.
Another cause of contaminated fuel is sediment on the bottom of
fuel tanks. Suction from underground storage tanks to the dispenser
is via a tube approximately 50mm from the bottom of the tank. This
50mm allows condensation, ground water ingress and flash rust to
accumulate. In the meantime tankers filling the tank at a rate of
1000L/minute via a 100mm drop tube will be agitating and
emulsifying tank bottom debris. So, when the tank is filled by the
petrol tanker, contaminants mix with the fuel being pumped into
your tank.
Diesel engines are especially susceptible the contaminated fuel
because the pumps and injectors have only very fine tolerances.
Petrol engines can also be affected by dirty fuel, which can cause
loss of power and detonation (also known as pinging), and can clog
up injectors. Along with contamination can come some very expensive
repair bills.
If you are a victim of contaminated fuel, you will experience rough
running, poor performance and increased fuel consumption.
Unfortunately, if these symptoms start to show the damage might
have already been done. If you are driving a petrol or early diesel
(pre-2000), hopefully all you will need to do is flush the fuel
system - which should include the diesel pump being drained, fuel
filter replaced and a new tank of clean fuel. Newer common rail
diesel engines aren't as lucky. If spores grow into algae the fine
tolerances in both the pump and injectors mean these parts of the
fuel system will clog and cause up to $15,000 in repairs that
aren't covered by a new car warranty.
There are some fuel treatment products on the market, mainly for
diesel engines - that help prevent the growth of algae and bacteria
during fuel storage and also prevent gum build up. A few brands
available are Chemtech Diesel Power, Fuel Doctors Australia, and
Wynns Spitfire Diesel Treatment. These products will help clean
your fuel system but are only preventative and will not actually
remove algae.
Another preventive step is to install an aftermarket water trap
after the original fuel filter. This will give you a glass fuel
bowl and another point in the system that water can be
trapped.
Dealing with fuel contamination is an exercise in prevention,
because if our vehicles are showing signs of having contaminated
fuel on board it is usually too late. Thousands of dollars worth of
damage can be done without you even knowing - so prevention is the
key.
Using a fuel treatment of some sort can help prevent air or water
borne spores from growing into algae in our tanks and also clean
our fuel system as we drive. But before you go out and buy one it
is best you speak with your mechanic first.
Being careful where we buy our fuel is another great way of
preventing contamination; this can be easy when you're filling up
at the same service station every week, but this is often
impossible when on the road.
Source: Camper Trailer Australia #44, Sep 2011
