Audi A4 Owners & Service Manuals

Audi A4: 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 indicator light. However, you should occasionally check the coolant level.

Messages

The following messages may appear depending on the vehicle equipment:

Turn off engine and check coolant level. See owner's manual

The coolant level is too low.

Stop driving and switch the engine off. Check the coolant level.

  • If the coolant level is too low, add coolant. Only continue driving once the indicator light turns off.

Coolant temperature: too high. Please let engine run while vehicle is stationary

Let the engine run at idle for a few minutes to cool off, until the indicator light turns off.

  • If the indicator light does not turn off, do not continue driving the vehicle. See an authorized Audi dealer or authorized Audi Service Facility for assistance.

Coolant system: malfunction! Please turn off engine

Do not continue driving, shut the engine off, and switch the ignition off. See an authorized Audi dealer or authorized Audi Service Facility for assistance.

Coolant additive

The coolant additive is made of anti-freezing and corrosion protection agents. Only add the following coolant additives mixed with distilled water.

Checking and Filling

The amount of coolant additive that needs to be mixed with water depends on the climate where the vehicle will be operated. If the coolant additive percentage is too low, the coolant can freeze and damage the engine.

Checking and Filling

Note

  • Before the start of winter, have an authorized Audi dealer or authorized Audi Service Facility check if the coolant additive in your vehicle matches the percentage appropriate for the climate. This is especially important when driving in colder climates.
  • If the G12evo coolant additive is not available in an emergency, do not add any other additive. You could damage the engine. If this happens, only use distilled water and restore the correct mixture ratio with the specified coolant additive as soon as possible.
  • Only refill with new coolant.
  • Radiator sealant must not be mixed with the coolant.
  • You can continue driving if the permitted G12evo coolant additive was not added.

    However, go to an authorized Audi dealer or authorized Audi Service Facility immediately to have the coolant replaced to reduce the risk of engine damage.

  • Due to the risk of engine damage, the cooling system should only be refilled by an authorized Audi dealer or authorized Audi Service Facility. An authorized Audi dealer or authorized Audi Service Facility can also provide you with important information about the recommended coolant additive.

Checking coolant

Checking and Filling
Fig. 160 Engine compartment - Coolant expansion tank (diagram): 1 cover with release button: 2 markings

Checking the coolant level

  • Park the vehicle on a level surface.
  • Switch the ignition off.
  • Open the hood.

The coolant expansion tank for some engines is located in the water drip tray under a cover. If necessary, remove the cover that is located under the windshield wiper on the front passenger's side.

  • Check the coolant level in the coolant expansion tank fig. 158 using the outer markings (2) > fig. 160. The coolant level must be between the markings (2) when the engine is cold. When the engine is warm it can be slightly above the upper marking.
  • Applies to: vehicles with 6-cylinder engine: There is a float located in the coolant expansion tank. Read the coolant level using the coolant level float. When the engine is cold, the float must be located between the MIN marking and the edge of the filler opening on the coolant expansion tank.
  • When you add coolant to the expansion tank, please refer to Cooling system.

Adding coolant

Requirement: there must be a residual amount of coolant in the expansion tank.

If you must add coolant, use a mixture of water and coolant additive. Audi recommends mixing the coolant additive with distilled water.

  • Allow the engine to cool.
  • Place a large, thick towel on the coolant expansion tank cap.
  • Push the release button (1) > fig. 160 on the cap and carefully turn it to the left until you feel resistance.
  • Push the release button again and remove the cap completely.
  • Add coolant in the correct mixture ratio up to the MAX marking. Or, in vehicles with a 6-cylinder gasoline engine, the float must be located between the MIN marking and the edge of the filler opening on the coolant expansion tank.
  • Make sure that the fluid level remains stable.

    Add more coolant if necessary.

  • Vehicles with 6-cylinder engine: if necessary, press the float into the coolant expansion tank using the cover.
  • Turn the cap to the right to tighten it until you feel resistance a second time.

Coolant loss usually indicates that there is a leak.

Immediately drive your vehicle to an authorized Audi dealer or authorized Audi Service Facility and have the cooling system inspected. If the cooling system is not leaking, coolant loss can result from the coolant boiling due overheating and then being forced out of the cooling system.

WARNING

  • The motor compartment in any vehicle is a potentially dangerous area. Stop the engine, switch the ignition off, and allow the engine to cool before working in the engine compartment.

    Always follow the information found in General information.

  • Never open the hood if you can see or hear steam or coolant escaping from the motor compartment. This increases the risk of burns. The cooling system is under pressure.

    When you no longer see or hear steam or coolant escaping, you may open the motor compartment with caution.

  • When working in the engine compartment, remember that the radiator fan can switch on even if the ignition is switched off, which increases the risk of injury.
  • Coolant additive and coolant can be dangerous to your health. For this reason, store the coolant in the original container and away from children. There is a risk of poisoning.

Note

Do not continue driving if the coolant expansion tank is empty. Do not add any coolant, because air could enter the cooling system and damage the engine. See an authorized Audi dealer or authorized Audi Service Facility for assistance.

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