E46: CCV + Intake Re-con.

Following on from this post - E46: Inlet full of oil! Re-con time. - where I discovered the intake-manifold was full of oil, I decided to give the entire thing a good clean out. The sensors, actuator and throttle-body were removed and given a good rinse with brake-cleaner. There was still oil pooling in the manifold, so I just kept on squirting brake-cleaner down the ports and turning the manifold round to run it all back to the main plenum. The Vanos [or Valvetec, whatever] seemed to benefit the most from this as the tubes were full of oil and sticking a bit. They now slide up and down freely and hopefully the electronic-actuator will still work now its clean.

The CCV sits below the inlet-manifold in a plastic-housing, along with the main wiring-loom box. Separately it looks like the diagram. These are known as 'vortex' type breathers, as crankcase pressure is relieved from the head via tube [3] and oil is separated in a spiral and runs down tube [4] back to the sump. The air-pressure is then vented via a diaphragm through tube [2] into the throttle-body, which provides a constant vacuum that keeps the engine as a suitable idle. When the vortex is clogged with oil and rust, pressure builds up in tube [3] and backs up into the head, down into the crankcase and forces oil and air back up tube [4]. This then pushes the diaphragm back and allows the oil up tube [2] into the inlet-manifold. This is clear in my case by the wiring-connectors to the other end of tube [2] and the diff.-pressure sensor being filled up with oil past the metal prongs.

Stripped, the CCV looks like this. The diaphragm housing was completely jammed solid with oily crud, which had leaked round the whole housing. The spiral oil-seperator was clogged with oily rust, which took a lot of getting out. All items were soaked in brake-cleaner and left in the parts-basin at work, then the oil-seperator was blown through with 200psi from the airline. Eventually I got quite a lot of air-flow through the vortex and the diaphragm-housing was squeaky clean, so I threw it back together and refitted the CCV and manifold. I've saved £45 on the part and this quick-fix should work for enough time at least for me to rule the CCV out if the problem persists. If it goes and comes back, £45 is not a lot to spend and I will be glad to do so if it cures the low idle problem!