Driver Knowledge Tests

Can you be fined for having a smoky vehicle exhaust?

Exhaust pollutants are a major health issue and the NSW Environmental Protection Agency and various agencies are committed to reducing unnecessary pollution from badly maintained engines.

If your vehicle emits exhaust fumes for more than 10 seconds, you could be fined $400 if you’re driving a commercial vehicle, or $319 for any other vehicle, but this fine is more in certain places. 3 demerit points can be issued for creating unnecessary smoke.

Fines of $2000 are being issued for smoky vehicles in the M5 East Tunnel (captured by sensors and a camera), with a third conviction attracting an automatic three-month suspension of the vehicle’s registration, as well as another $2000 fine. Some companies have been fined 5-figure sums for multiple infringements.

As defined in the Protection of the Environment Operations Act 1997, a smoky vehicle is one that emits excessive air impurities if:

  1. when in operation, it emits as determined in accordance with the regulations, air impurities in excess of the standard of concentration and the rate (or the standard of concentration or the rate) prescribed in respect of the class of motor vehicles to which the motor vehicle belongs, or
  2. when tested in the prescribed manner, it emits air impurities in excess of the amount per test prescribed in respect of the class of motor vehicles to which the motor vehicle belongs.

There has been a smoky vehicle program since the 1970s. Over 1000 reports are made every month of smoky vehicles. You can report a smoky vehicle here.

Diagnosing the cause of a smoky vehicle

Diesel-powered vehicles

Many older diesel-powered vehicles will produce more visible smoke, but the time limit of 10 seconds ensures that vehicles with defects are captured.

White smoke is caused by fuel not burning – look for low compression, a faulty injection system or incorrect timing.

Blue smoke is caused by engine oil getting into the pistons and being burned – look for the engine oil level being too high, or engine wear in the pistons, rings, valves, guides, seals and rings.

Black or grey smoke is caused by incomplete fuel combustion. Many diesels do produce black or grey smoke under heavy acceleration. It can be caused by a clogged air filter, incorrect timing, a faulty injection system or an overheating engine.

Petrol-powered vehicles

Petrol-powered vehicles should not emit any smoke unless they are a specific type of two-stroke engine or an older rotary.

As with a diesel-power motor, blue smoke indicates oil is being burned – check engine oil level, wear and tear in the engine, and turbo pressure seals.

A small amount of black or grey smoke may be emitted under full acceleration, but not an undue amount. Larger amounts of smoke are caused by a clogged air filter, incorrect ignition timing, a blocked manifold, or issues with the choke, fuel injections, carburettor or emissions systems.

Darren is an expert on driving and transport, and is a member of the Institute of Advanced Motorists

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