Volvo D11F Operator's Manual And Maintenance Instructions page 37

Safety Information 33
Crushing or Cutting Prevention
Before working on a vehicle, set the parking brakes, place the transmission
in neutral and chock the wheels. Failure to do so can result in unexpected
vehicle movement and can cause serious personal injury or death.
DO NOT work near the fan with the engine running or the ignition in the
ON position. The engine fan can engage at any time without warning.
Anyone near the fan when it turns on could be seriously injured.
Never attempt adjustments or repairs while the engine is running, see your
authorized Volvo Truck dealer.
Inspect the fan blade assembly before service for cracks or loose mounting
before starting the engine. Never stand alongside a rotating fan assembly,
particularly at high fan speeds.
Wear protective glasses when striking objects to avoid injury to your eyes.
Chips or other debris can fly off objects that are struck. Make sure no one can
be injured by flying debris before striking any object.