Oil below airbox
 

Hi all. Two days ago I went for a simple service check and as soon as the car has been placed on the bridge we saw some oil traces.
After had removed the carters we found some oil all around pieces N°5, all around direction bocal, and also a small quantity inside the carbon box, where the hose n°3 is plugged :


http://ills.bmwfans.info/199d.png


I called a well known specialist in France to get his opinion. It seems that CHF is not concerned. It is not sticky and not red, looks like oil (clear).
For him it is probably the hose n°3 who is dead. He also advice to change piece n°1 (oil separator).

Did you ever met this kind of trouble ? Do you have an idea ?

This hose n°3 is plugged on the airbox, I am not a specialist (far from), so could someone explain to me why is there a link with oil? What is the purpose of this hose ?

Thanks and sorry if I am not clear, a technical mail in English is not simple to write for me :)
http://fr.bmwfans.info/parts-catalog...oil_separator/

Where does 5 go from too

i am sure 5 goes back to the sump its a breather system


the small amount of oil in the air box is normal

yes seem to remember it goes to the sump case next to the dipstick ,,

The diagnosis given but my mechanic seems to be good for you ? Hose 3 to replace?

Hello Olive,

First.. the Oil lines are there for when the oil gets hot, it evaporates a bit. Normally you would just make it exit the engine for good or make it go into a canister (catch can) but because of regulations it is forbidden for any Oil to permanently exit the engine, so the engineers made it so the oil gasses get diverted into the induction airbox. So basically the engine is designed to inhale its own blow-by gasses.

So a bit of oily-ness inside the airbox is perfectly normal, however it shouldn't have puddles of oil in there.

In your case i think that some pipe going to the underside of the airbox must be leaking? I think a gunked up oil seperator is not the issue, but im no car mechanic, so take with a grain of salt.
It is however not very expensive to replace (around 100€) and should be done at around 100.000km anyway, imho.


I would disconnect the pipes you've mentioned and check whether they still are free. And if in doubt replace them.

Thanks a lot Julian for this clear answer. I will let you know the news tomorrow 👍:beer:

You're welcome mate. :thumbs:

I received a picture from the garage.

On collar was missing (normal ?) on this small hose, the collar bellow has been added by the garage.

https://zupimages.net/up/18/37/wu52.jpg

It seems there is no problem with hoses anywhere. Do you think it could comes from here ?

One more point.
The garage asked me about the tightening torque of the rear axle input nut. This is the one that holds the shaft of attachment of the shaft of transmission.


I know...I am not very clear. Here the piece I am looking for the torque :


https://zupimages.net/up/18/37/qtfq.jpg


Somebody ?:beer: