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Coolant AN Line Upgrade Install

Part Available: TGK Motorsports AN Coolant Line Upgrade Kit

  1. Remove Headlight Plastic Covers
    For the S7, remove any plastic covers around the headlights to access the radiator area. This step does not apply to the S6.

  2. Remove Radiator Cover
    Detach the radiator cover by removing the two plastic pins at the top. Set the cover aside.

  3. Remove Underneath Plastic Cover
    With the radiator cover removed, locate and unscrew the three T30 bolts beneath it to detach the additional plastic cover.

  4. Remove Intake
    Remove the intake to access the coolant lines and components.

  5. Remove Intake Air Guide
    If using a factory intake, remove the two T30 bolts securing the air guide. For aftermarket intakes, use the appropriate Allen wrench.

  6. Remove Splash Shields
    Pull back or remove the splash shields beneath the vehicle to access the lower cooling system components.

  7. Drain Coolant

    • Place a suitable coolant catch pan underneath the car and ensure the engine is cool to avoid burns.
    • Carefully open the coolant reservoir cap with a cloth to relieve any pressure, preventing hot coolant from spraying.
    • Using a Phillips-head screwdriver, open the coolant drain plug to let the system drain completely.

    WARNING: The cooling system will require additional tools for full draining and filling; follow Audi’s coolant filling and bleeding procedures to prevent air pockets and overheating.


  8. Disconnect OEM Coolant Lines

    Lift up on the release tabs of the OEM coolant lines, then pull them straight out to disconnect. Expect some residual coolant to drain out, so keep a rag or container ready.

    Remove OEM Fittings

  9. Install AN Adapters

    Install the AN adapters by double-wrenching each securely. Ensure that each adapter is seated properly to prevent leaks.

  10. Route and Install AN Lines

    • Route the front coolant line, using both 45-degree and 90-degree connectors.
    • Avoid the factory path; route the lines around the front of the engine and through the center of the core support to the radiator for optimal clearance and fit.

    Routing AN Lines

  11. Connect to Coolant Crossover Line

    Use the supplied barb fitting to attach the AN line to the coolant crossover line on the passenger side. Tip: Temporarily removing the rubber crossover hose can make it easier to attach the barb fitting before re-securing.

    Connecting to Crossover Line

  12. Refill Coolant

    • Refill the coolant system with Audi-approved coolant mixed with distilled water according to Audi’s recommended ratios (e.g., 50% coolant and 50% water for most regions - using distilled water prevents mineral deposits and corrosion)
    • Fill the system up to the recommended level, as marked on the coolant reservoir.

    Note: Use the VAS6096 or similar coolant filling tool if available to eliminate air pockets during the refill process.


  13. Bleed Air from the System

    • Remove the upper cowl cover and open the bleed port.
    • Allow coolant to flow from the bleed port until no air bubbles are visible.
    • Close the bleed port and reinstall the cowl cover.
    • Jack up the passenger side of the car to assisthelp inmove removingany trapped air from the system.
    • Remove the upper cowl cover, then locate and opentoward the bleed port.
    • AllowSet coolantthe heater to flowhigh steadily(HI) fromwith the bleedfan holeon untillow noto airopen bubblesthe areheater visible.core.
    • SecureReopen the bleed port andbriefly reinstallto release any remaining air from the cowlheater cover.core area.
    • Turn off the A/C (ensure the LED in the A/C button is off).
    • Run the engine at 3500 RPM for about 4 minutes to push coolant through the system.
    • Allow the engine to idle until the temperature gauge reaches 90°C (194°F) and both heater hoses are warm.
    • Run the engine at 2000 RPM for 2 more minutes to ensure full circulation.

    Important: Once the system is bled, run the engine as specified in Audi’s service guide, typically at idle and then at 2000 RPM, to circulate coolant fully and confirm no air pockets remain.


Following these detailed steps should ensure a secure, leak-free installation of the TGK AN coolant lines. Refer to TGK Motorsports and Audi’s maintenance manuals for additional insights and troubleshooting support.

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