2021 Audi A5 Quattro Radiator Fan Isn't Working

Fix Non-Functioning Radiator Fan in 2021 Audi A5 Quattro

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
34% chance it's the
Fan Motor or Clutch
0%
28% chance it's the
Fan Relay or Fuse
0%
23% chance it's the
Temp Sensor or Fan Control Module
0%
15% chance it's
Something else
The most common reasons a 2021 Audi A5 Quattro radiator fan isn't working are the fan assembly, the fan clutch, or the coolant temperature sensor.
  • Fan Motor or Clutch: A faulty fan motor or a malfunctioning fan clutch can result in inadequate cooling, causing the engine to overheat.
  • Fan Relay or Fuse: A faulty fan relay or blown fuse can prevent the cooling fan from operating, leading to engine overheating.
  • Temp Sensor or Fan Control Module: A faulty temperature sensor or fan control module can result in incorrect readings, causing the engine to overheat or the cooling fan to operate improperly.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2021 Audi A5 Quattro radiator fan isn't working?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

Over time serpentine belts stretch, crack, and the ribs that ride on the accessory pulleys being to wear smooth. A squealing noise that increases with engine speed or as engine driven accessories are turned on may be noted. The noise is caused by the belt slipping on the pulleys, insufficiently driving them. Ineffective air conditioning, a battery warning light, or intermittent power steering assist can result from this.

»MORE: Symptoms of a bad serpentine belt

The bad thermostat can cause two different sets of problems, depending on whether it's stuck open or stuck closed.

A thermostat that is stuck open can cause the engine to run colder than normal and turn on the check engine light. It may also cause poor fuel mileage and the heater to blow cool air.

A thermostat that is stuck closed will cause the vehicle to overheat. If a new thermostat doesn't resolve engine temperature problems, the cooling system needs to be checked for other issues.

» LEARN MORE: Signs of a bad thermostat, and how to fix it

When the engine coolant temperature sensor fails, it will send inaccurate information to the vehicle’s computer, causing the computer to react to false operating conditions. This will cause the engine to consume more fuel than normal, depleting fuel mileage, and causing black, sooty smoke from the engine under moderate to heavy acceleration. The check engine light will illuminate, and on-board diagnostic trouble codes may be stored for exhaust and emission system failure, fuel delivery system failure, and engine cooling system failure. Overheating may also occur, as the coolant sensor may be leaking fluid out of the engine, creating a an air pocket in the system.

What are the steps to diagnose the non-functioning radiator fan in a 2021 Audi A5 Quattro?

To diagnose a non-functioning radiator fan in your 2021 Audi A5 Quattro, begin with the simplest checks to avoid unnecessary complications. Start by inspecting the fuse associated with the radiator fan; a blown fuse is a common and easily fixable issue that can halt fan operation. If the fuse is intact, proceed to examine the relay that controls the fan, as a malfunctioning relay can also prevent the fan from activating. Next, test the fan motor directly by applying power to it; if it fails to operate, the motor may need replacement. Additionally, check the temperature sensor, which is vital for triggering the fan when the engine reaches a certain temperature. Look for any wiring issues, such as frayed wires or loose connections, as these can disrupt the fan's functionality. Finally, using a diagnostic tool to scan for error codes can provide further insights into any underlying problems within the cooling system. By following this structured approach, you can effectively identify and address the issue with your radiator fan.

What are the common causes for the radiator fan not working in a 2021 Audi A5 Quattro?

When dealing with a non-functioning radiator fan in a 2021 Audi A5 Quattro, it's essential to consider several common problems that could be at play. One of the primary culprits is a faulty fan motor, which may require replacement to restore functionality. Additionally, a blown fuse can interrupt the power supply to the fan, so checking the fuses is a straightforward first step. Another potential issue is a malfunctioning temperature sensor, which may fail to signal the fan to activate when the engine reaches a certain temperature; replacing this sensor can often resolve the problem. Wiring issues, such as damaged or loose connections, can also prevent the fan from operating correctly, making it crucial to inspect the wiring thoroughly. Lastly, low coolant levels can lead to overheating, which may cause the fan to stop working as intended; ensuring that the coolant is at the proper level can help mitigate this risk. By systematically addressing these common causes, DIYers can effectively troubleshoot and potentially fix the radiator fan issue in their Audi A5 Quattro.

How urgent is it to repair the non-working radiator fan in a 2021 Audi A5 Quattro?

When faced with a non-working radiator fan in your 2021 Audi A5 Quattro, the urgency of repair cannot be overstated. The radiator fan is essential for regulating the engine's temperature, and its failure can lead to severe overheating, which poses a significant risk to your engine's integrity. Ignoring this issue may result in costly repairs, such as warped cylinder heads or blown head gaskets, which can escalate quickly if the problem is not addressed. Additionally, operating your vehicle under these conditions can strain other engine components, leading to further complications down the line. For those considering a DIY approach, it is crucial to diagnose the problem accurately and understand the potential risks involved. While some may attempt to troubleshoot or replace the fan themselves, consulting a professional mechanic is often advisable to ensure that the repair is done correctly and to safeguard against future issues. Prioritizing the repair of your radiator fan will not only enhance your vehicle's performance but also protect your investment in the long run.

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