Crankcase Breather Hoses

First Line have recently started to offer six crankcase breather hoses (emissions hoses) for BMW applications which are available to order from FPS.

Crankcase ventilation is a key aspect of modern engine design. Even in a new engine, combustion pressure will force vapor and oil deposits past the piston rings and into the crankcase.

To avoid a build-up of excess pressure, the crankcase must be vented. Old vehicles used to vent these combustion by-products to atmosphere, which was obviously not good for the environment. Modern engines use Positive Crankcase Ventilation (PCV) to vent the by-product into the inlet manifold via a PCV valve. This regulates the evacuation of the gases for optimum engine running.

The hoses from the crankcase to the PCV valve often get clogged with oil deposits, and can also turn brittle and split due to the constant heat cycles they endure, not to mention being attacked by the oil itself. This process is often accelerated in the cold weather.

Symptoms of clogged or failed breather hoses are:

  • Poor idling
  • Lack of engine power/responsiveness
  • Oil fumes and oil leaks.

First Line therefore offer a small range of Crankcase Breather Hoses.