This bulletin applies to all Volkswagen vehicles that are equipped with a turbocharger suspected with a boost leak.
According to Volkswagen, use of a smoke machine is not recommended for testing boost leaks.
Follow the procedures in the repair manual (engine, engine mechanical, 21 – turbo charger G charger, charge air system – checking for leaks).
Use soapy water on all lines and connections to trace a possible leak after the system is pressurized.
According to VW, a smoke machine does not build enough pressure to thoroughly test this system in the event of a leak.