Emptied my catch can today, was amazed how much oil was in there! This is after just a few weeks! Definatly a worthwhile mod looking at this.

Drain mine about once a month

is that oil or water?

I cant see if thats oil you would have to top up constantly.

Personally dont see the point in them as the only thing that goes thru is vapour so would be burnt off, with that its dry all the time?

just my thoughts

nice mix tho

There a must billy !!! Hot oil vapour !!

Defo worth doing !!

I was always under impression that abit of oil vapour into intake was a good thing to help lubricate bottom of valve stems or is that not as important on modern engines

they make it like that for a reason so I will be leaving it lol.

never had a prob.

for a top powered car that you want to keep maxed then yea but for a daily car I would of thought it would keep things lubricated? as said, seems a nice idea to me to have it and any that gets right thru gets burned. having said that there is hardly anything in my intake track and ive not touched it since putting the FMIC on in 2008 and done 20k+ a year between 2009 and dec 2011.

So is that oil then? or water from the condensation build up when engine cools?

It's probably about 95+% water.

The catch can acts as a perfect condenser unit in the winter (aluminium can sat at the front of the bay). That's why the cans don't fill up in the summer, only during the colder months.

Leave the mixture for a few hours to separate and you'll see.

The standard breather system hugs the engine closely and is made from plastic and rubber, so the water vapour never gets the chance to condense. The engine just sucks the moist air back in and burns it (to it's advantage).

seems worthwhile on my diesel, although I went for the pikey route of a just an elephant mod :-) No need to clean all the black tar from the EGR or inlet manifold, or have oil dribbling from the bottom of the intercooler.

must admit that fabia needs one.

The only reason the pcv system is plumbed back into the intake as standard is for emmisson purposes,no other reason,old cars just a pipe coming out the block pointing to the ground.

I cleaned about half a mugful of oil and water out of my inlet pipework once, I can't imagine it helps boost cooling when it gets into the intercooler.

The only reason the pcv system is plumbed back into the intake as standard is for emmisson purposes,no other reason,old cars just a pipe coming out the block pointing to the ground.

So if thats true then why do these cars run **** when vented to air?

The whole system is preasurised is it not while running?

So if thats true then why do these cars run **** when vented to air?

The system expect a certain amount of air to passed back through (which isn't metered by the MAF). Therefore by venting this air, the engine is getting less air than it is expecting...

Yep, that and the amount of air that is supposed to be recirculated from the divertor valve. Take both of those bits of unmetered air away and the air:fuel ratio goes up the creek.

But then Oil Catch Cans usually have a tube going back to the inlet so air can get back in, and they just condense and collect the oil and water.

seems worthwhile on my diesel, although I went for the pikey route of a just an elephant mod :-) No need to clean all the black tar from the EGR or inlet manifold, or have oil dribbling from the bottom of the intercooler.

I've been thinking of doing this to my A4. Do you think it's worth it?