Audi A4 Owners & Service Manuals

Audi A4: Motor compartment

General information

Special care is required if you are working in the motor compartment

For work in the motor compartment, such as checking and filling fluids, there is a risk of injury, scalding, accidents, and burns. For this reason, follow all the warnings and general safety precautions provided in the following information.

The vehicle's motor compartment is a dangerous area.

Explanation of warning symbols:

Hot motor components! Rotating parts!

The radiator fan can switch on at any time!

High voltage! Switch off the engine before coming into contact with any ignition system components!

The catalytic converter can be damaged the oil level is too high!

Hot coolant - there is a risk of scalding!

Always follow the instructions in the operating manual.


  • Turn the engine off.
  • Switch the ignition off.
  • Set the parking brake.
  • Select the "P" (Park) selector lever position.
  • Allow the engine to cool.
  • Keep children away from the motor compartment.
  • Never spill fluids on a hot engine. These fluids (such as the freeze protection contained in the coolant) can catch fire.
  • Avoid short circuits in the electrical system.
  • Never reach into the radiator fan. The fan is temperature-controlled and can turn on suddenly, even when the ignition is switched off.
  • Never open the hood when there is steam or coolant escaping from the motor compartment, because there is a risk that you could be burned. Wait until no steam or coolant is escaping.
  • The cap on the coolant expansion tank must never be opened when the coolant is hot.

    The cooling system is under pressure. There is a risk of burns

  • To protect your face, hands, and arms from hot steam or coolant, cover the cap with a thick cloth when opening.
  • Do not remove the engine cover under any circumstances. This increases the risk of burns.
  • Due to the risk of electric shock, never touch the ignition cable or other components in the electronic high-voltage ignition system when the engine is running or is starting.
  • If a gear is engaged while the vehicle is stationary and the engine is running, do not press the accelerator pedal inadvertently.

    Pressing the accelerator pedal will cause the vehicle to move, and this could result in an accident.

  • If inspections or repairs must be performed while the engine is running, moving components (such as the ribbed belt, generator, and radiator fan) pose an additional risk.
    • Set the parking brake first and select the "p" (Park) selector lever position.
    • Always make sure that no parts of the body, jewelry, ties, loose clothing, and long hair can be caught in moving engine components. Before any work, always remove any jewelry and/or ties, tie back long hair, and make sure all clothing fits close to the body to reduce the risk of anything becoming caught in engine components.
  • Pay attention to the following warnings listed when work on the fuel system or on the electrical equipment is required.
  • Do not smoke.
  • Never work near open flames.
  • Always have a working fire extinguisher nearby.
  • All work on the battery or electrical system in your vehicle can result in injuries, chemical burns, accidents, or burns. Because of this, all work must be performed only by an authorized Audi dealer or authorized Audi Service Facility.
  • Limit your exposure to exhaust and chemicals to as short a time as possible.


California Proposition 65 Warning:

  • Engine exhaust, some of its constituents, and certain vehicle components contain or emit chemicals known to the State of California to cause cancer and birth defects and reproductive harm. In addition, certain fluids contained in vehicles and certain products of component wear contain or emit chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.
  • Battery posts, terminals and related accessories contain lead and lead compounds, chemicals known to the State of California to cause cancer and reproductive harms.

    Wash hands after handling.


When filling fluids, be sure not to add any fluids to the wrong reservoirs. Otherwise severe malfunctions and engine damage will occur.

For the sake of the environment

You should regularly check the ground under your vehicle in order to detect leaks quickly. If there are visible spots from oil or other fluids, bring your vehicle to an authorized Audi dealer or authorized Audi Service Facility to be checked.

Opening and closing the hood

The hood is released from inside the vehicle.

Checking and Filling
Fig. 156 Footwell: release level

Checking and Filling
Fig. 157 Unlocked hood: lever

Observe the safety precautions General information.

Make sure the wiper arms are not raised up from the windshield. Otherwise the paint could be damaged.

Opening the hood

  • With the door open, pull the lever below the instrument panel in the direction of the arrow > fig. 156.
  • Raise the hood slightly.
  • Press the lever > fig. 157 in the direction of the arrow. This releases the hooks.
  • Open the hood.

Closing the hood

  • Push the hood down until you override the force of the struts.
  • Let the hood fall lightly into the latch. Do not press it in.


The following messages may appear depending on the vehicle equipment:

warning! Hood is not locked. Stop vehicle and check the lock

The hood latch is not locked correctly. Stop immediately and close the hood.


  • Never open the hood when there is steam or coolant escaping from the motor compartment, because there is a risk that you could be burned. Wait until no steam or coolant is escaping.
  • For safety reasons, the hood must always be latched securely while driving. Because of this, always check the hood after closing it to make sure it is latched correctly. The hood is latched if the front corners cannot be lifted.
  • If you notice that the hood is not latched while you are driving, stop immediately and close it, because driving when the hood is not latched increases the risk of an accident.

Motor compartment overview

The most important check points.

Checking and Filling
Fig. 158 Engine compartment overview: diagram

Observe the safety precautions General information.

  1. Washer fluid reservoir ()
  2. Jump start points: (+) under the cover, Charging the 12 volt vehicle battery, Jump starting
  3. Engine oil filler opening ()
  4. Sticker* for engine oil specifications
  5. Coolant expansion tank ()
  6. Brake fluid reservoir ()

The coolant expansion tank and the engine oil filling opening may be located in different places within the engine compartment, depending on the engine version.


     Engine oil

    If the engine oil level too low If you need to add engine oil, use an oil that is listed on the sticker. The sticker is located at the front of the engine compartment fig. 158. When using the engine

     Cooling system

    Coolant The engine cooling system is filled with a mixture of purified water and coolant additive at the factory. This coolant must not be not changed. The coolant level is monitored using the indi

     Brake fluid

    Fig. 161 Motor compartment: cap on brake fluid reservoir Observe the safety precautions General information. Checking the brake fluid level The brake fluid reservoir is located under a cover on the d


     Speaker Trim in Door Trim Panels, Removing and Installing

    Special tools and workshop equipment required Pry Lever -80-200- Front Bass Speaker Trim, Removing - Carefully pry out the speaker trim -1- along the door trim panel seam using the Pry Lever -80-200- in the direction of -arrow A-. - Disengage the speaker trim at the rear from the door

     Front Seats

    Component Location Overview - Electric and Electronic Components 1 - Memory Seat/Steering Column Adjustment Control Module Memory Seat/Steering Column Adjustment Control Module -J136- Front Passenger Memory Seat Control Module -J521- Equipped on some models: Integrated seat ventilat

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