PCV Vent Hose Leak

pysical

Sergeant
Jun 16, 2017
471
108
0
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2009 335xi E90
Anyone had an issue with this? I did a VC job and got some burning oil smell and a little bit of smoke on top/rear engine. Thought it was the VC gasket until more research. Look at the PCV vent hose and bunch of oil around it and dripping towards back of VC. So I took it off, cleaned it all up, cleaned the RB valve (external pcv kit) and plan on driving it for few days to let oil burn off and then check to see if it is leaking again. Just wanted to check and see if anyone had a issue with this hose not seating properly? It is at a little angle and the passenger side of the hose is not pushed in as far as the driver side. But, it is all the way on and the clips are holding it on like it should. Was thinking maybe a bigger o-ring next time, but that shouldn't be the solution.
 

dyezak

Major
May 4, 2017
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With the description you gave it sounds like you are talking about the flapper valve hose. If that is correct then yes. New clips are available and help.
 

pysical

Sergeant
Jun 16, 2017
471
108
0
Ride
2009 335xi E90
I am talking about this: 11157553949

All clips are holding it on. But it allowed oil to come out of it and spew on the back of the valve cover, run down the valve cover, and end up burning and smoking. I am not sure why this would be doing it? New VC and new vent hose. Just checking to see if anyone had oil leaking from that hose and what you did to fix it.
 

dyezak

Major
May 4, 2017
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Yep, that's the flapper valve (so called because of the box in the hose has a flapper in it). If it's leaking at the VC connection and the clips are seated fully that's a new one on me. Usually the only time I've had that issue is if the clips weren't seating correctly.

What's your crankcase pressure like? If you have excess crankcase pressure I could see this being an extenuating circumstance too as the flapper would seal under boost, the crankcase pressure would increase, and if the clips on this hose weren't seated correctly you'd get a leak here.

You can do a boost leak test and see how much leakage you are getting into the crankcase by checking your oil fill. Mine was horrible and when I opened the oil fill cap during my boost leak test the cap went flying off (had about 5psi of pressure in it). Plugging the intake ports with the RB intake port plugs fixed this for me.
141721_x800.jpg
 

pysical

Sergeant
Jun 16, 2017
471
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2009 335xi E90
I have yet to do a leak down test. I am not sure what that consists of so if you know of a DIY that is pretty simple please link it.

But I do have my head ports plugged from the RB external kit.
 

dyezak

Major
May 4, 2017
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I'd do both a boost leak test and a leakdown test too. Leakdown is through the sparkplug holes and boost leak is through the intake ports. Your boost leak test is easy and cheap and tells you if you have any leaks in your intake tract, and in your specific situation if your PCV system is sealing adequately. A leakdown test takes a special tool to put in place of your sparkplugs and connects to your compressor, it pressurizes your cylinder and tells you how well your cylinders are sealing. If you have blowby issues pressurizing your crankcase you'll find it with this test.
 

pysical

Sergeant
Jun 16, 2017
471
108
0
Ride
2009 335xi E90
I'd do both a boost leak test and a leakdown test too. Leakdown is through the sparkplug holes and boost leak is through the intake ports. Your boost leak test is easy and cheap and tells you if you have any leaks in your intake tract, and in your specific situation if your PCV system is sealing adequately. A leakdown test takes a special tool to put in place of your sparkplugs and connects to your compressor, it pressurizes your cylinder and tells you how well your cylinders are sealing. If you have blowby issues pressurizing your crankcase you'll find it with this test.

The engine was just rebuilt about 1.5k miles ago. I will look into the boost leak test though.
 

dyezak

Major
May 4, 2017
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The cheapest and first step should be removing the hose and just checking to make sure nothing (grit grime etc) is preventing it from getting a good seal. But I kind of assumed you did that. Decided not to make an ass out of us, so I'll bring it up :)
 

pysical

Sergeant
Jun 16, 2017
471
108
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2009 335xi E90
Yeah over the weekend I removed it. Cleaned up all the oil. Wiped down everything, applied oil to the oring and put it back on.
 

pysical

Sergeant
Jun 16, 2017
471
108
0
Ride
2009 335xi E90

Here are two pictures I just took. It is leaking right now. The first picture shows how it sits. But it is connected and the clips are hooked.

Second picture shows where it is leaking down to the back of the VC.

The only other thing that could be leaking MAYBE is the RB valve??? Which I doubt it?
 

dyezak

Major
May 4, 2017
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The only other thing that could be leaking MAYBE is the RB valve??? Which I doubt it?

If the RB valve is clogged and not functioning then it could exacerbate the issue. Just pull it out really quick (it just popps out) and give it the ole suck blow test. Just have a beer handy to wash your mouth out after hahahah.
 

pysical

Sergeant
Jun 16, 2017
471
108
0
Ride
2009 335xi E90
Yeah that thing works. I also cleaned it out over the weekend when I did the vent hose. I made sure I could blow out towards the catch can but not the other way. Also got a little bit of oil in the can.