Fuel Tank Functions

2009 BMW X5 35dSECTION Fuel Tank Functions

A pressure relief valve (B) is integrated in the fuel filler cap (A) to protect the fuel tank (E) from excess pressure. A non-return flap (C) is located at the end of the fuel filler neck.

The non-return flap prevents the fuel from sloshing back into the fuel filler neck. The components in the fuel tank can be reached via the two service caps (F). The fuel fill level can be determined via the two lever-type sensors (G). The surge chamber (D) ensures that the fuel pump always has enough fuel available for delivery.

Fig 1: Fuel Tank Function Diagram
G06896050Courtesy of BMW OF NORTH AMERICA, INC.
INDEX EXPLANATION CHART

Index Explanation
A Fuel filler cap
B Pressure relief valve
C Non-return valve
D Surge chamber
E Fuel tank
F Service cap
G Lever-type sensors
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.