Working on components in the engine compartmentWorking on components in the engine 
compartment  - Bonnet - Checking and topping up fluids - General maintenance - Audi S5 Owner's Manual - Audi S5

Extra caution is necessary when working on components in the engine compartment.

Always be aware of the danger of injury and scalding as well as the risk of accident or fire when working in the engine compartment (e.g. when checking and refilling fluids). Always observe the warnings listed below and follow all normal safety precautions. The engine compartment of any motor vehicle is a potentially hazardous area. ⇒ WARNING.

WARNING
Х Switch off the engine.
Х Remove the ignition key.
Х Apply the parking brake.
Х Move the gear lever into neutral.
Х Wait for the engine to cool down.
Х Keep children away from engine compartment.
Х Never spill fluids on hot engine components. These fluids can cause a fire (e.g. radiator anti-freeze).
Х Take care not to cause short circuits in the electrical system, especially when working on the battery.
Х Do not touch the radiator fan when the engine is hot. The fan may start running suddenly.
Х Do not unscrew the cap on the expansion tank when the engine is hot. The cooling system is under pressure.
Х Protect face, hands and arms by covering the cap with a large, thick rag to protect against escaping coolant and steam.
Х If any tests have to be performed with the engine running, there is an extra safety risk from the rotating parts, such as the drive belts, alternator and radiator fan, etc., and from the highvoltage ignition system.
Х Observe the following additional warnings if work on the fuel system or the electrical system is necessary:
− Always disconnect the battery.
− Do not smoke.
− Never work near naked flames.
− Always keep an approved fire extinguisher immediately available.

Caution
When topping up fluids make sure the correct fluid is put into the correct filler opening. This can otherwise cause serious malfunctions or engine damage.

For the sake of the environment
Inspect the ground underneath your vehicle regularly so that any leaks are detected at an early stage. If you find oil spots or other fluids, have your vehicle inspected by a qualified workshop.

Note
On right-hand drive vehicles* some of the containers/ reservoirs mentioned below are located on the other side of the engine compartment.