Checking charge air system for leaks, vehicles with one turbocharger — AUDI

🧭 Before you start

Fits: Audi A6/A7 C7 (4G, 2011–2018)

• Special tools named: V.A.G 1687/3, V.A.G 1687, V.A.G 1842
• Renewed: gasket
• Also covered elsewhere: Operating instructions

Don't miss

• If there is water in sight glass, remove drain plug (6) and drain water.
• Risk of damage if pressure is set too high.The pressure must not exceed 0.5 bar. — Adjust pressure to 0.5 bar via pressure control valve (2).

🔧 Engine codes this applies to

📐 1 workshop diagram for CDUC

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. Remove engine cover panel .
2. Release hose clips (arrows) and remove air pipe (1).
3. ⚠ Depending on the vehicle version and country version, a crankcase breather hose may be fitted which cannot be detached from the cylinder head cover without being damaged irreparably. For these versions, the hose on the cylinder head cover will be damaged irreparably and must then be renewed. — Remove crankcase breather hose (arrow); to do so, press release tabs (if present) or break hose connection at cylinder head cover as necessary.
4. Seal connection for crankcase breather on turbocharger with adapter 1687/17.
5. Connect end seal V.A.G 1687/3 to turbocharger with adapter 1687/16.

6. Release hose clip (arrow) and detach air hose.
7. Connect adapter1687/11 to air hose going to throttle valve module J338.
8. Connect hose (1) of charge air system tester V.A.G 1687 to adapter.
9. Unscrew pressure control valve (2) completely and close valves (3) and (4).
10. Using a commercially available connection piece, connect charge air system testerV.A.G 1687 to compressed air (1). [Note: If there is water in sight glass, remove drain plug (6) and drain water.]
11. Open valve (3).
12. ⚠ Risk of damage if pressure is set too high.The pressure must not exceed 0.5 bar. — Adjust pressure to 0.5 bar via pressure control valve (2).
13. Open valve (4) and wait until test system is pressurised. If necessary, adjust pressure to 0.5 bar again.
14. Check charge air system for audible leaks or leaks that can be felt with the hand; apply commercially available leak detecting spray or use ultrasonic testerV.A.G 1842. [Note: A small amount of air escapes through the valves and enters the engine. Therefore it is not possible to perform a pressure retention test.For operation of ultrasonic tester V.A.G 1842, refer to Operating instructions.Release pressure in test circuit by detaching hose coupling from adapter before removing adapter.] [Note: Renew gasket and O-rings.]

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