I. Core function and structure
★ Core function
The fuel tank vent pipe OE code No. 13907636133 is used to balance the air pressure inside and outside the fuel tank, preventing pressure imbalance due to fuel evaporation or temperature changes, and avoiding deformation of the fuel tank or direct emission of fuel vapors into the atmosphere.
The BMW fuel tank vent valve is integrated into the fuel tank cap and contains an air valve and a vapor valve, which control the vacuum pressure (opens below 98kPa) and the overpressure relief (opens above 120kPa) respectively.
★ Associated components
The vent pipe works in conjunction with the carbon tank, fuel pump bulkhead, and fuel vapor recovery system, and abnormalities may lead to abnormal noise or fuel leakage.
II. Common Faults and Detection
★ Failure phenomenon Cause analysis Detection method
Fuel tank rattling (popping sound) Ventilator clogging or carbon canister failure, resulting in an imbalance of air pressure 24 Check the sealing of the fuel tank lid and carbon canister adsorption capacity.
Cold start white smoke Ventilator condensate is not discharged in a timely manner, mixed into the exhaust system4 Observe whether the exhaust pipe drain hole is blocked.
Engine malfunction light is on Ventilation pipe valve is not closed tightly (such as the 2019 5-series common) 5 Use a diagnostic instrument to read the EVAP system fault code.
III. Repair and Replacement Program
★ Key Repair Points
Ventilator replacement: original parts need to match the number (e.g., 2019 5-series replacement interval can be as short as 10,000 kilometers), and sub-factory parts need to verify the sealing of the interface.
Carbon Canister Cleaning/Replacement: If the carbon canister is saturated and the vapor cannot be adsorbed, the vent pipe seal needs to be replaced at the same time.
★ Operation Precautions
Empty the fuel before disassembling the tank to avoid static electricity causing safety hazards;
The fuel evaporation system needs to be reset after replacement (e.g. ISTA software calibration).
IV. Maintenance Recommendations
★ Preventive inspection
Every 20,000 kilometers to check the vent pipe interface oil stains or deformation, focusing on the observation of the breathing port at the top of the fuel tank;
Vehicles traveling short distances for long periods of time need to be driven at high speeds periodically to promote carbon canister desorption.
★ Upgrade Program
High-frequency failure models (e.g. old X1, 3 series) can be replaced with metal-reinforced ventilator hose, which improves anti-aging performance by 30%.
V. Accessory Reference
Type of parts Adapted to the car model Example of original manufacturer's number
Fuel Tank Vent Pipe Assembly BMW 5 Series (G30) VIN code is required for accurate search.
Carbon canister assembly X1/X3/3 Series (with N20/B48 engine)