Purpose of Crankcase breather/airbox breather hose?

[VW Caddy]

Hi All,

Just wondering if anybody could explain the purpose of a Crankcase breather/airbox breather hose?

If i leave the hose exposed would that be a bad thing? If so, are there any ways to not make it so bad?

Reason I'm asking is because I want to install a make-shift air intake but because my car has that hose connected to the airbox, i don't if i should or not.

Cheers,

[gotrice]

Crankcase venting is really important. You dont want any presure in the CC and if you can you want a vac pump on there to create negitive pressure in the CC.
But you could have your line to the CC up somewhere high in the engine bay (if you put it low there will be oil everywhere - I have first hand experience on this one LOL. MMI (Maron Motorsport International) wont touch my car now coz of it) with its own filter. Its not legal but it will work just fine.

[VW Caddy]

I think i have that vac pump already on there, because that what that CC hose comes out from (pic below - hose going into the bottom of the airbox)




I would've thought that by putting the CC hose somewhere high in the engine bay would be a lot more messy wouldn't it? Also, the excess oil coming out of that hose is going back into the intake tube.........isn't that a bad thing?

Do you think the best thing to do would be to place the CC hose in the make-shift intake? If so, would it best to place it before the air filter?

Cheers

[peedman]

The excess oil gets burnt up, its like that for all cars. You can run a catch can but i dont see the point on a road car.

[Guest0608]

from the picture you are showing, that's the secondary air pump that is coming from the airbox. This pump is electrically driven and runs only for 15 seconds when the car is first started up from stone cold. it drags extra air and dumps it into the cylinder head for a better clean burn and better emissions when first starting the car. If your car is parked over night and cold, open the bonnet before you start the car, disconnect the hose from the airbox by pushing in the 2 little tabs and start the car, you will feel it sucking like a vac cleaner for only 15 seconds and thats it until next time you start from stone cold. So for your question you need to keep this pipe connected to the electric pump and install a filter on the end to keep the crap out of your engine. disconnecting or unplugging the pump will put the epc light on the dash!! (make sure nothing gets sucked through when doing the test!) They had these on the MK4 golf also and Ive seen cone filters fitted and also a mini filter fitted the the pump hose, not sure where you can get them tho, but if getting the after market cone filter they should tell you about that anyway.