How to fix thermostat stuck Audi Q5

Fixing a Stuck Thermostat on an Audi Q5 (8R) (2008-2017)

Tools Required

• Socket set (including Torx and Allen sockets)
• Ratchet wrench
• Torque wrench
• Drain pan
• Coolant funnel
• Infrared thermometer
• Cooling system pressure tester
• Replacement thermostat and gasket
• New coolant (compatible with Audi specifications)
• Hose clamp pliers

Repair Instructions

Step 1: Prepare the Vehicle

• Ensure Safety: Park the vehicle on a level surface, engage the parking brake, and disconnect the negative battery terminal.
• Drain Coolant:
  • Place a drain pan beneath the radiator.
  • Open the radiator drain plug or remove the lower radiator hose to drain the coolant.

Step 2: Access the Thermostat

• Remove Engine Covers:
  • Detach any plastic covers obstructing access to the engine.
• Locate the Thermostat Housing:
  • Follow the upper radiator hose to the engine block; the thermostat is located where the hose connects.

Step 3: Remove the Thermostat

• Detach the Radiator Hose:
  • Use hose clamp pliers to remove the clamp securing the hose to the thermostat housing and carefully detach the hose.
• Remove Thermostat Housing Bolts:
  • Use the appropriate socket to remove the bolts securing the thermostat housing.
• Extract the Old Thermostat:
  • Note the orientation of the thermostat before removal.
  • Remove the thermostat and gasket.

Step 4: Install the New Thermostat

• Install New Gasket:
  • Clean the mating surfaces of the housing and engine block.
  • Place the new gasket on the thermostat housing.
• Insert New Thermostat:
  • Ensure the thermostat is correctly oriented (spring side towards the engine).
• Reattach Thermostat Housing:
  • Secure the housing with bolts, tightening them to the manufacturer’s torque specifications.

Step 5: Reassemble and Refill Coolant

• Reconnect Radiator Hose:
  • Attach the hose back to the thermostat housing and secure it with the clamp.
• Refill Coolant:
  • Use a coolant funnel to refill the system with new coolant.
  • Ensure the system is bled of air by opening the bleeder valve (if equipped) or running the engine with the heater on until air bubbles cease.

Step 6: Test the Repair

• Check for Leaks:
  • Start the engine and let it reach operating temperature, checking for leaks around the thermostat housing.
• Verify Temperature Stability:
  • Ensure the temperature gauge stabilizes at a normal operating level.
• Final Inspection:
  • Reinstall any removed engine covers and reconnect the battery.

Conclusion

A stuck thermostat can cause significant engine issues if not addressed promptly. Following these detailed steps will ensure a proper repair, restoring the cooling system's functionality. Always refer to the service manual for specific torque specifications and coolant recommendations for the Audi Q5.