What's this pipe for ??

[tosh23]

Vectra 1.9 cdti 120 2007 manual

On or near the bottom of the air box ( air filter housing) there is a pipe that is as thick as your thumb, The airbox has a hole on the bottom so it cant be a drain hole for water. I was just wondering what it was called and what does it do ? Thankyou Tosh

[tosh23]

Ive found out that it is the PCV..Or crankcase pressure control valve..
If Im understanding it right.....It takes the crankcase pressure made from worn rings or worn valve seats in the bore and pumps the oil misted pressurised air back into the airbox when the air intake needs clean dry air for the injection system...Another EGR, but this time..crankcase pressure recirculation...Is that right??

Question 2..
If the tube from the crankcase PC Valve that plugs into the airbox was disconnected from the airbox and allowed to just flop around what would that do to the smooth running of the engine...IF ANYTHING?...

Thankyou for taking the time to read this....Tosh

[alcutler]

Vectra 1.9 cdti 120 2007 manual

On or near the bottom of the air box ( air filter housing) there is a pipe that is as thick as your thumb, The airbox has a hole on the bottom so it cant be a drain hole for water. I was just wondering what it was called and what does it do ? Thankyou Tosh

Are you sure this pipe shouldn't be fitted into the hole in the airbox - I have the older 120 and the rubber hose which has an oval slightly elongated end pushes into this hole and has a groove moulded into it to hold it in place - its a right pig to get back in. I understood it was a drain in case any water or condensation should form in the filter airbox, although I have never looked to see where the other end goes! - Forgive me if I'm wrong - they may have changed it with the facelift.

[Critch]

Sounds like the pipe thats for draining water from airbox

Pcv( positive crankcase ventilation) is for emissions. As back in the old days crank case gases where vented to atmosphere. Now with tighter emissions control the gases are emitted back into intake to be re used.

[Critch]

Sounds like the pipe thats for draining water from airbox

Pcv( positive crankcase ventilation) is for emissions. As back in the old days crank case gases where vented to atmosphere. Now with tighter emissions control the gases are emitted back into intake to be re used.

[Critch]

Sounds like the pipe thats for draining water from airbox

Pcv( positive crankcase ventilation) is for emissions. As back in the old days crank case gases where vented to atmosphere. Now with tighter emissions control the gases are emitted back into intake to be re used.

[tosh23]

Thank You very much for all your replies,
I have looked at the air box and indeed there is a hole at the bottom of the box for water expellation
It looks like it is a return for the crankcase breather into atmospheric pressure...
I will endeavour to install said pipe back into its original home after all it cant do any harm.
Im slowly and methodically going through the engine to find why my MPG is down to 33..(in town)
I was going down the line of..a sensor that tells the ECU that the engine is cold which in turn makes the engine run rich ( possibly/ (choke like )).
The thermostat is working within normal parameters
With the car being an estate the regen comes on roughly every 200 miles..
Which leads me to believe that the air/diesel mix is on the rich side and cokes up the exhaust ...
Ohh well back to the drawing board...Once again thankyou to all for your ideas and replys....Tosh

[troutybrown]

Have you tried the coolant temperature sensor. If this is reading low then the ECU could be fuelling for a cold engine.

[tosh23]

Bingo..
Many many thanks for that
That is what I was looking for...
Time to do some more research
Once again...Thankyou.....Tosh

[alcutler]

Sounds like the pipe thats for draining water from airbox

Pcv( positive crankcase ventilation) is for emissions. As back in the old days crank case gases where vented to atmosphere. Now with tighter emissions control the gases are emitted back into intake to be re used.

Ok Mate we get the point