078131101AC New Secondary Air Ventilation Injection Check Valve for AUDI A4 A6 S6 S8 VOLKSWAGEN PASSAT TOUAREG 078131101AG

• How does a check valve work? A car's check valve is like a "one-way switch": When fluid (air/exhaust gas) flows forward, the pressure pushes open the internal valve flap/reed, letting the fluid pass through smoothly. Once the fluid tries to flow in reverse, the reverse pressure shoves the valve flap back to its sealing position, and the valve closes automatically to block the backflow — this prevents equipment damage, pressure surges, or exhaust gas abnormalities. Features  •   Automatic on-off, One-way conduction ,High adaptability Benefits  •   Reduce the risk of damage to pipelines/engine components •   No complex electrical control components and low failure rate •   Aid in optimizing engine exhaust/intake efficiency  • O.E.M Replace: 078131101AC/078131101AD/078131101AG/078131101F/078131101N Compatible Vehicles: for   AUDI A4 1996-2001 for   AUDI A6 1998-2004 for   AUDI A8 2000-2006 for   AUDI S6 2002-2003 for   AUDI S8 2001-2003 for   VOLKSWAGEN PASSAT 1998-2005 for   VOLKSWAGEN…