Crankcase breather / oil separator

R0B

Member
My 1.4 petrol has suddenly developed a thirst for oil. I have not experienced any loss of performance so I'm hoping that means the engine hasn't lunched its piston rings which i know is a common issue on these engines. However, i have noticed mayo in the oil filler behind the service flap so im thinking that the breather system may be blocked and the pressure is pushing oil up here.

im thinking about replacing the oil separator and breather pipework with new items but there appears to be two styles of oil separator. Does anyone know if the two styles interchangeable? Also, has anyone ever changed the breather system so that it vents to atmosphere or run a catch can to do away with the oil separator completely? If so how did you do it?

Thanks
Rob
 

nuttinnew

A2OC Donor
The two aren't interchangeable.
I've had mine replaced (at about 100k) but not the hoses, they seemed ok.
It's made a world of difference, night and day difference re oil consumption, and the whole situation has reminded me of the 'dalek' on the early small block VAG water cooled engines which was something you expected to renew at intervals.
 

esamk

Member
is it the black plastic 'box' which sits above the sump at the back of the engine?
Did you change it yourself. if so was it easy to change? did you have to remove the subframe to access the breather system?
I have a wiff of oil smell coming into my car and it appears that there is a small oil leak coming from the back of my engine. the cover gasket seems fine, so i am lead to believe it could be the oil separator.
 

Birchall

Dick Chown Award 2016
As far as the oil smell in the car is concerned. Have you checked the rubber stoppers under the bonnet ?

when you lift the bonnet off you will see where the water drains out of the air box. These holes should have special rubber bungs tgat let water through but do not let the smell enter the air intake.
If they are there still just check that they close properly. (They are just like a pair of lips that are in the "normally closed position" (sometimes I wish my wife had those! - only kidding of course). If these bungs are missing or not closing properly you will get the oil smell in the car.

In your case where you are indicating an oil problem anyway the smell is likely to be worse than normal.
But it is worth checking the bungs anyway.

Steve B
 

esamk

Member
Thanks Steve,
When i purchased the car a few months back, i noticed one of the bungs was missing so ordered a new one. I was hoping that would be the end to it.
The remaining bung on the other side and one on the air duct near the bulkhead were already present and appear to be in good condition.
i suspect that some of the oil leaking from the rear of the engine maybe falling onto the hot exhaust which is what i think i'm smelling. Just need to know if the sub frame needs to be removed to access the oil separator. its a 1.4 pertol AUA engine. the oil separator appears to be only held in by 3 bolts.
 

6stings

A2OC Donor
I have noticed that I have the oil separator leakage on my 1.6 FSI while the car was at the service this week, it wasn't much, no dripping.
Can't say that the oil consumption has changed or anything. I asked the guys about the breather, they weren't worried about it.
It looks like something I can replace myself, there's not lot of space, but it can be reached from the bottom side.
I would have it replaced, but couldn't wait for the part one more day...

Just found the part numbers for 1.6 FSI

036103464AC oil separator
N 90617501 o-ring; 60X4
036103677 o-ring
N 10248801 socket head bolt with; inner multipoint head; M6X30
N 10248804 socket head bolt with; inner multipoint head; M6X30

I think these o-rings are leaking...
 
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bretti_kivi

Member
mine too, but I replaced mine back in December. It was a true ***** of a job, because the top part wouldn't come loose. 10 min for everything else, 90 minutes of cursing. Then had to take it back off because there were two seals in place....

if your garage will do it for cheap, go for it. For me, it took 2 hours @ €30/ hour - I figured it would be less than one or I would have had it done by the garage.

- Bret
 

6stings

A2OC Donor
mine too, but I replaced mine back in December. It was a true ***** of a job, because the top part wouldn't come loose. 10 min for everything else, 90 minutes of cursing. Then had to take it back off because there were two seals in place....

if your garage will do it for cheap, go for it. For me, it took 2 hours @ €30/ hour - I figured it would be less than one or I would have had it done by the garage.

- Bret
I ordered the parts and the breather hose too, I'm replacing everything soon.
There is no €30/hour garage here, Bret, my dentist charges less per hour than the garage.
I'll go for the 90 minutes cursing, I think.
 

6stings

A2OC Donor
Well, the parts are in the house, but where this 036103493DN goes, I wonder? I can't find it on the drawing buy it was on the parts list!?

It's on the right on the picture.

A2 16fsi oil separator and breather pipes.jpg

A2 16fsi oil separator no19.jpg

A2 16fsi vent hose no28.jpg

A2 16fsi oil separator and breather pipes order.jpg
 

Birchall

Dick Chown Award 2016
If you google just the part number 036103493DN you will get an explanation of the part and a picture of where it goes (from parts base)

Steve B
 

6stings

A2OC Donor
I did. You can't find it on any BAD engine illustration. It has the same number (28) as the 036103493CG, but I can't see it.
 
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6stings

A2OC Donor
Doesn't look the same, Steve.
I ordered it just because there were two 19's on the diagram. The 'CG' pipe and this weird 'DN' kind of pipe with the belly.
It's little strange that there are two parts listed and only one is on the diagram.
and I have checked the part numbers on the parts themselves, they are correct.

The good thing is, if the weird 'DN' kind of pipe with belly doesn't exist on my engine, than it's not leaking either :)

Two 28's, not 19's, sorry about the mistake.
 
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spike

Well-Known Member
The two pipes look like the end connection points are almost identical.
If this is true then I suspect its an 'either or' situation and the last pipe is the latest version. The extra chamber will be to improve oil mist separation from the crankcase blowby gases, reducing the oil being recirculated back into the intake which in turn will reduce emissions.
That's the theory anyway.

Cheers Spike
 

6stings

A2OC Donor
That's a good theory!
I would expect them to have both ends angled the same way, but they don't. If the 90 degrees angled ends are positioned in the same direction, parallel, the ends on the other side don't point in the same direction.

image.jpg

image.jpg

image.jpg

image.jpg
 

madalina

Member
Hy guys, is it normal to have so much water and mayonnaise in the oil breather. I got at least half a glass of water for it and a cup of mayonnaise and the tube that goes from it to the throttle body it's full with the same stuff-- it drips water from it when I took it out from the breather. I get also a strange behavior with the car--- it goes from normal sound of an engine to a diesel like noise and a weird sound under the right fender; more like a air sound pumped in a bottle or like a drum....
 

6stings

A2OC Donor
Hy guys, is it normal to have so much water and mayonnaise in the oil breather. I got at least half a glass of water for it and a cup of mayonnaise and the tube that goes from it to the throttle body it's full with the same stuff-- it drips water from it when I took it out from the breather. I get also a strange behavior with the car--- it goes from normal sound of an engine to a diesel like noise and a weird sound under the right fender; more like a air sound pumped in a bottle or like a drum....
Hi Madalina, I think you are talking about the black tube that goes from the throttle to the oil cap on the top of the engine. The crankcase breather / oil separator is placed at the back of the 1.6 FSI engine, and it's accessible only from the bottom, it's not easy to reach to it.
Your description makes me think of water/fume condensation. I have seen the 'mayonnaise' under the oil cap on 1.6 A3 I bought used 4-5 years ago, the guy who sold it to me wasn't used the car more than once a week, if that.
 
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madalina

Member
I'm talking about that black box behind the engine hold by 3 screws. I don't know why I can't upload pictures but I can tell that this is not normal. It's too much. I took out the oil pan and clean everything there but I think that something is not working right. Is it possible that this valve is bad and all the moisture and the vapor it's not been evacuated from the engine properly?
 
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