Patching Audi Crankcase Breather Module

Oct. 3, 2022

2 min read

This bulletin applies to 2013-2016 Audi A6, S6, A7, S7, A8 and S8 vehicles equipped with a 4.0L engine. A metallic whistling or grinding noise may be heard from the engine area when at idle speed. The sound usually only occurs when the engine is warm, and the MIL may be sporadically on. DTCs may be stored in the ECM including P227900 (intake air system leak) and/or P050700 (idle control system rpm higher than expected).

A leak in the crankcase breather module (pressure regulating valve) can cause this condition. A fabric-reinforced internal membrane of the crankcase breather module has been developed. Open the filler cap to check whether the sound is affected when the cap is open. If so, replace the oil separator breather module.

Parts required are as follows:

- 079103542E..........oil separator

- 079129717J...........left intercooler gasket

- 079129717K..........right intercooler gasket

- N90442501............retaining clips (two)

- N90489801............retaining clips (two)

About the Author

Information courtesy of Mitchell 1

Information for Technical Service Bulletins comes from ProDemand, Mitchell 1's auto repair information software for domestic and import vehicles. Headquartered in San Diego, Mitchell 1 has provided quality repair information solutions to the automotive industry since 1918.

Mike Mavrigian

Motor Age Editor

Mike Mavrigian has written thousands of automotive technical magazine articles involving a variety of specialties, from engine building to wheel alignment, and has authored more than a dozen books that crisscross the automotive spectrum. Mike operates Birchwood Automotive, an Ohio shop that builds custom engines and performs vintage vehicle restorations. The shop also features a professional photo studio to document projects and to create images for articles and books.