Cummins 4BT – Venting the Fuel Systems

Controlled venting is provided at the injection pump through the fuel drain manifold. Small amounts of air
introduced by changing the filters or injection pump supยญply line will be vented automatically if the fuel filter is
changed in accordance with the instructions.

However, manual bleeding will be required if:
โ€ข The fuel filter is not filled prior to installation.
โ€ข Fuel injection pump is replaced.
โ€ข High pressure fuel line connections are loosened or lines replaced.
โ€ข Initial engine start up or start up after an extended period of no engine operation.