Product Information
Genuine Audi Vacuum Hose
This Vacuum Hose Assembly is found on S4/S5/S5 Sportback/SQ5/SQ5 Sportback Models with Engine Code - CWGD. It is important to verify the condition of your existing Vacuum Hose Assembly as many EA839 2.9T/3.0T Models are experiencing Vacuum System Contamination following the failure of the Engine Water Pump. If Engine Coolant is found in the Vacuum Hose Assembly, while performing the Engine Water Pump Service, it is very important to clean out the lines and check the condition and operation of the N649 - Mechanical Coolant Pump Switch Valve. If Engine Coolant has reached the N649 Valve, we recommend replacing the entire Vacuum Hose Assembly.
Please See Below: There are (2) Revisions of the N649 Valve based on Production Date, please take into consideration prior to ordering.
- N649 Valve - Pre-Production Date Split
- N649 Valve - Post-Production Date Split
Vacuum Hose
A Vacuum Hose is a flexible rubber or plastic tube in a vehicle that carries vacuum (negative air pressure) from the intake manifold or vacuum pump to various engine components. Many automotive systems rely on engine vacuum for proper operation, including the brake booster, emissions controls, fuel pressure regulator, and HVAC controls.
Vacuum Hose Failure Symptoms
- Rough idle or stalling – unmetered air entering the engine disrupts the fuel-air mixture.
- Hissing noise under the hood – sound of air leaking from a broken or loose hose.
- Poor acceleration / loss of power – incorrect air-fuel ratio affects combustion.
- Check Engine Light (CEL) – often triggered by lean condition codes (P0171, P0174).
