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1.0 List of Critical Failures

There are described in the next pages the most common Safety Critical Failures that can affect to the
vehicle safety. They are mentioned according to the area of the vehicle where they can be located.

1.1 Engine

If the vehicle has a leak of diesel, oil or coolant, and is dripping, it should not be driven lest it causes a fire or
damages the engine.
If the leak is dripping near or onto a source of heat, the engine must be stopped immediately and they must
report it to the person in charge at the garage in each case and wait for further instructions.
It is important to watch the dripping in case the liquid sets fire because of the high temperature.
If the vehicle leaks coolant and the source can’t be found. For example, check the information on this in the
vehicle’s maintenance history.

Exhaust leaks produce uncontrolled sources of heat. These can affect sensitive parts of the vehicle.
Pay special attention to broken screws of the manifold, broken exhaust clamps, cracked exhaust manifolds.
Cracked or loose intercooler tubes, etc. may make the vehicle lose power and drag large amounts of sprayed oil
over the open area of the engine and this mist of oil and air could reach a source of heat.

If there are any signs of low oil pressure, the engine must be stopped immediately.
Low oil pressure is linked to poor engine lubrication and this will unavoidably damage the engine in very little
time.

If the engine’s firefighting system becomes damaged or deactivated, this could put the passengers’ safety at
risk, as well as the vehicle’s safety, in the event of a fire.

If the vehicle’s dashboard shows a warning of low oil level or low coolant level, these should be refilled under
the supervision of the person in charge of the garage.

1.2 Gearbox

If an oil leak drips onto, or leave traces of oil on the connector, stop the vehicle. Otherwise, the gearbox could
be seriously damaged.

If the driver notices marked slipping or friction when changing gears, this could mean a deficient working
pressure, which can seriously damage the gearbox.

If it is difficult to put the car into a certain gear or once it’s in the gear, it comes out and goes into neutral gear.

1.3 Brakes

Loss of air in the pneumatic system could render the brakes useless or lock the vehicle.

Global Maintenance Standard: Safety Critical Defects 5