Crankcase breather 320d E91 -09?

Gaspo · 04-17-2016, 12:33 PM

Hello guys i know there's not to many diesel BMW engines running in the us. But I will give my question a go.

I have a 320d E91 and I wonder about the crankcase breather. As I had understand it is built in to the valve cover and works completely different than regular crankcase breathers. Post nr seven in this thread is what it looks like:http://www.e90post.com/forums/showthread.php?t=442397. And as you se there's a pipe on it. On that pipe there is a hose that goes done to the hose frome the air box up to the turbo.

My question is that it come some oil from the valve cover pipe in to the hose that goes down to the hose from the air box. When i unmont that hose I se some oil in the air box hose bottom. I changed the hose that goes frome the valve cover the old one was all dirty and oily. The new one has been clean. But today i saw that a tiny tiny bit of oil had leaked at the upper side of the hose. Maybe it's bad construction or so.

But my maine consern is the oil. I have read a little bit about crankcase breathers and some say it normal that it comes oil frome it.

I hope you guys understand my poor english hard to explain when your not that good on it :-(

Nodrog29 · 05-27-2016, 04:01 AM

I'm having similar issues with a 2009 E91 320d as well, I noticed oil around the pipe from the crankcase breather to the air intake. I think its also the cause of a bit of oil being around the bottom of the charge hoses on the hot and cold side of the intercooler. I originally thought the turbo was the cause of the oil but the turbo is fine and the source of the leak is the pipe you were talking about.

I've replaced the pipe but I don't think there was much wrong with the original one. All the guides on crankcase breathers relate to older M47 engines and I haven't seen a single mention of the N47 engine.

I chatted to a guy at BMW and he said you need to replace the entire rocker cover as the crankcase breather is non-serviceable. I have also got excessive crankcase pressure as I can feel the exhaust pulses through the oil filler cap and the dipstick. I'm hoping its crankcase breather related and not worn piston rings although I don't know what could be blocked as it's the venture type and it looks fine when I take the small circular cap off next to the oil filler cap.

Do you have normal crankcase pressure on your 320d?

Chippy1950 · 05-15-2022, 06:39 PM

Hi, I'am having the same issues as you explain. Did you ever get to the bottom of the issue with excessive air being felt when the filler cap was open. The air is strong on my car and pulsating as you explained. Was is the piston rings in the end?

P14kle · 05-16-2022, 01:53 AM

You need to change the valve cover gasket. Over time they go hard and brittle.

The Turbo pressure can then push air past the gasket as the crankcase breather system is built into the valve cover. This can pressurise the crankcase and push oil out through the breather system and through the turbo. Fills the whole intercooler/turbo system with oil eventually.

Chippy1950 · 05-18-2022, 12:25 PM

Thank P14kle
8000miles ago the valve cover + gasket was replaced with genuine OEM parts from BMW.
I have recently noticed that oil is leaking from the rear corner and also sitting in the injector wells again but it has taken a lot of miles to do this as I have been keeping an eye on it
I am going to look at replacing the gasket again and seeing if it hold better this time. Is there anything else to look at which could be causing this issue.?

04-17-2016, 12:33 PM	#1
Gaspo Private First Class 34 Rep 128 Posts Drives: E91 320D -2009 Join Date: Dec 2011 Location: Sweden iTrader: (0)	Crankcase breather 320d E91 -09? Hello guys i know there's not to many diesel BMW engines running in the us. But I will give my question a go. I have a 320d E91 and I wonder about the crankcase breather. As I had understand it is built in to the valve cover and works completely different than regular crankcase breathers. Post nr seven in this thread is what it looks like:http://www.e90post.com/forums/showthread.php?t=442397. And as you se there's a pipe on it. On that pipe there is a hose that goes done to the hose frome the air box up to the turbo. My question is that it come some oil from the valve cover pipe in to the hose that goes down to the hose from the air box. When i unmont that hose I se some oil in the air box hose bottom. I changed the hose that goes frome the valve cover the old one was all dirty and oily. The new one has been clean. But today i saw that a tiny tiny bit of oil had leaked at the upper side of the hose. Maybe it's bad construction or so. But my maine consern is the oil. I have read a little bit about crankcase breathers and some say it normal that it comes oil frome it. I hope you guys understand my poor english hard to explain when your not that good on it :-(
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05-27-2016, 04:01 AM	#2
Nodrog29 Lover of fast estate cars 6 Rep 19 Posts Drives: G21 LCI M340i (due Sept 22) Join Date: May 2016 Location: Barnstaple iTrader: (0)	I'm having similar issues with a 2009 E91 320d as well, I noticed oil around the pipe from the crankcase breather to the air intake. I think its also the cause of a bit of oil being around the bottom of the charge hoses on the hot and cold side of the intercooler. I originally thought the turbo was the cause of the oil but the turbo is fine and the source of the leak is the pipe you were talking about. I've replaced the pipe but I don't think there was much wrong with the original one. All the guides on crankcase breathers relate to older M47 engines and I haven't seen a single mention of the N47 engine. I chatted to a guy at BMW and he said you need to replace the entire rocker cover as the crankcase breather is non-serviceable. I have also got excessive crankcase pressure as I can feel the exhaust pulses through the oil filler cap and the dipstick. I'm hoping its crankcase breather related and not worn piston rings although I don't know what could be blocked as it's the venture type and it looks fine when I take the small circular cap off next to the oil filler cap. Do you have normal crankcase pressure on your 320d?
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05-15-2022, 06:39 PM	#3
Chippy1950 Registered 0 Rep 3 Posts Drives: BMW E91 320d 184bhp Join Date: Mar 2021 Location: London iTrader: (0)	Hi, I'am having the same issues as you explain. Did you ever get to the bottom of the issue with excessive air being felt when the filler cap was open. The air is strong on my car and pulsating as you explained. Was is the piston rings in the end?
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05-16-2022, 01:53 AM	#4
P14kle Second Lieutenant 196 Rep 291 Posts Drives: E91 Join Date: Dec 2015 Location: South West UK iTrader: (0)	You need to change the valve cover gasket. Over time they go hard and brittle. The Turbo pressure can then push air past the gasket as the crankcase breather system is built into the valve cover. This can pressurise the crankcase and push oil out through the breather system and through the turbo. Fills the whole intercooler/turbo system with oil eventually.
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05-18-2022, 12:25 PM	#5
Chippy1950 Registered 0 Rep 3 Posts Drives: BMW E91 320d 184bhp Join Date: Mar 2021 Location: London iTrader: (0)	Thank P14kle 8000miles ago the valve cover + gasket was replaced with genuine OEM parts from BMW. I have recently noticed that oil is leaking from the rear corner and also sitting in the injector wells again but it has taken a lot of miles to do this as I have been keeping an eye on it I am going to look at replacing the gasket again and seeing if it hold better this time. Is there anything else to look at which could be causing this issue.?
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