Leak Test Fuel Tank and Tank Ventilation System

Conducting Leak Test On Fuel Tank And Tank Ventilation System


NOTE:
Charge fuel tank and tank ventilation system with pressure.
During the leak test with a leak detector, be sure to follow the operating instructions of the equipment manufacturer.




Caution!

Escaping fuel vapors; only work in well-ventilated rooms or use suitable exhaust extraction unit.
Observe country-specific accident prevention and occupational safety regulations.







The leak test can be carried out with a leak detector.

Possible causes may be:
- Fuel filler cap leaky
- Tank ventilation lines leaky (fuel tank-activated carbon canister-tank ventilation valve)
- Tank ventilation valve leaky (engine compartment)
- Tank sensor on fuel tank leaky
- Activated carbon canister non-return valve leaky (spare wheel recess)

To make sure that the tank-venting valve (engine compartment) does not leak, carry out the following work steps.







Detach scavenging air line (1) and disconnect from tank-venting valve.


NOTE: The M73 is fitted with two tank-venting valves.







Seal scavenging air line with special tool 16 1 162.


Carry out another leak test as described above.
If no further leaks can be detected, the tank-venting valve is leaking and must be replaced.
If the system continues to leak, carry out a leak test.


NOTE: On the M73, first seal one tank-venting valve and carry out leak test, then seal second tank-venting valve and repeat leak test again. Replace leaking tank-venting valve.