[index1489]

Anyone with a 325i or 330i replace their oil separator?

Where you able to do it without removing the intake manifold?


This only applies to the 2006 N52 with the Magnesium valve cover, the 2007+ N52KP with the plastic cover has the separator built into the valve cover and is not serviceable as a separate part. (This also applies to the N54/N55).

Makes sense because I can't even find someone mention the word OIL Separator on this boards.

[Johnny D]

I have moved mine over to a different manifold when I did the three stage conversion. I dont see how you could remove/replace without first removing the intake manifold.

[index1489]

How hard is it to remove the manifold, say after you remove the microfilter and all that plastic shit out of the way, did you have to replace the gasket, is it a single gasket or bunch of small ones.
Thanks!

[RupertPupkin]

OP what is this? Can you show a pic or something? Didnt even knwo this was a part on our n52...

[index1489]

Its mounted on the side of the motor all the way to the back under the intake manifold.

This is not a good pic,

You should also change all the hoses, hose number 3 connects to the back of the valve cover, they are brittle plastic hoses and always break, when the dealer did my valve ticking recall and removed the valve cover they didn't replace the hose, Im certain they messed it up.

The oil separator is 60-70ish, hoses are 40-50 ish a piece for the 3 you need.


It's not difficult to do once the manifold is off, my bentley manual suggests its possible to replace it without removing the manifold by removing the air filter housing and attacking it at that angle.

[Phil325i]

Why not just tap into one of the pipes and plumb in an Oil Catch Tank?

[Johnny D]

Originally Posted by index1489

How hard is it to remove the manifold, say after you remove the microfilter and all that plastic shit out of the way, did you have to replace the gasket, is it a single gasket or bunch of small ones.
Thanks!

It's not extremely difficult, but it's not easy either. You could probably get the manifold unbolted and after removing the vent hoses (if they dont break ) move the manifold a few inches to get your hands in there. I couldnt...

Its 6 separate gaskets. They are cheap, just get new ones.

I've changed computers since I did the install so I don't have all of them, but here are a couple I do have. Unfortunately, all the good ones are on the other PC with a corrupt drive.
http://imgur.com/SSOdajI,NIAr2lm,Ynj...hgXZZK,eWlJsSu


Why are you replacing it? It doesn't seem like a part that needs replacing unless broken.

[index1489]

I'm having a weird noise/roughness at idle, I've gone around the world with it, and come back to oil seperator/hoses.

This all started shortly 5k miles after the dealer did my valve ticking recall.

Since then I've change just about everything.

Spark plugs
Ignition Coils
Intake/Exhaust Vanos Solenoids
Intake/Exhaust Camshaft Position Sensors
A Billion Bottles of Fuel Injector Cleaner from Redline, Chevron, Seafoam

Recently did the carbon cut out and cleaned the MAF.

Only thing left is my Oil Separator for the idle issue.

[aw3964]

I'm in the same boat but with a 06 530i N52.

Same issues as well. Does your RPM play get worse when you turn on the AC? Do you have to add a quart of oil every 800 miles with no sign of leak?


Those are pretty much my symptoms. The PCV was cracked and I changed that, but I shouldve done everything at one time.

Any on this job and has it fix your problem?

[wharper1970]

Originally Posted by aw3964

I'm in the same boat but with a 06 530i N52.

Same issues as well. Does your RPM play get worse when you turn on the AC? Do you have to add a quart of oil every 800 miles with no sign of leak?


Those are pretty much my symptoms. The PCV was cracked and I changed that, but I shouldve done everything at one time.

Any on this job and has it fix your problem?

did u ever find anything out? i have a 06 530i too same issues turning on AC causes SES light too rough idle etc...

[jeguth1s]

Originally Posted by Johnny D

It's not extremely difficult, but it's not easy either. You could probably get the manifold unbolted and after removing the vent hoses (if they dont break ) move the manifold a few inches to get your hands in there. I couldnt...

Its 6 separate gaskets. They are cheap, just get new ones.

I've changed computers since I did the install so I don't have all of them, but here are a couple I do have. Unfortunately, all the good ones are on the other PC with a corrupt drive.
http://imgur.com/SSOdajI,NIAr2lm,Ynj...hgXZZK,eWlJsSu


Why are you replacing it? It doesn't seem like a part that needs replacing unless broken.

+1. Not too difficult but a pain at the same time. The breather hoses are a PITA. If they haven't been replaced, you'll most likely break them. Once the manifold is off, the separator is easy to R&R. I replaced my starter, oil separator, intake gaskets, and throttle body gasket.

[index1489]

The only thing that's hard is removing the lower connection that goes to the oil pan, its a pain in the ass.

[Xpuzzle]

Originally Posted by jeguth1s

+1. Not too difficult but a pain at the same time. The breather hoses are a PITA. If they haven't been replaced, you'll most likely break them. Once the manifold is off, the separator is easy to R&R. I replaced my starter, oil separator, intake gaskets, and throttle body gasket.

I am replacing the starter in my 06 E90 325i. I have already unbolted the intake manifold and cleared all the hoses out of the way. While pulling out the manifold, saw that the oil separator was holding it back so I need to detach it. Is there a quick way to do this? Is there a screw or bolt holding it to the manifold?

Any help is appreciated.

[PhaseP]

The oil separator is bolted on to the manifold, I think two bolts but it has been a while I did this. I do not think you can unbolt it, you can't even see the bolts, but you can try maybe you will be able to.

What it really prevents you from pulling the manifold is the oil return line that goes from the oil separator down to a tube that goes into the oil pan.

There is also a electrical junction box that is bolted to the manifold at the lower side that will prevent you from lifting the manifold up. This junction box is bolted to the manifold with two torx bolts via a sheet metal piece of bracket. You can unbolt these if you remove the power steering reservoir out of the way (just remove it from its mounting place by two undoing two nuts and set it aside.) Some people separate the electrical junction box from the sheet metal bracket, but in my case it wasn't coming off. It is connected by something like barbed inserts and meant to be one time in.
You also need to disconnect the throttle body electrical connection there. You will probably need to disconnect the alternator control cable.
And I would suggest AFTER DISCONNECTING BATTERY, disconnect the alternator positive cable, which provides more movement of the manifold while working there. Alternator plus cable is I think live with battery positive cable, hence you need to disconnect battery otherwise it will spark anywhere it touches.

I think you will have to disconnect an electrical connection that goes to another very small junction near the oil separator that distributes voltage to all the heaters on the oil separator related lines/hoses. You cannot see this also, just need to find by feel and use a thin flat screw driver to pry on side and pull it out. It has a notch on onside that holds in place. Which side? you need to test.

Now coming back to oil return line on the oil separator, that is the biggest hurdle. Disconnecting that oil return line from the separator is not easy simple because there is not much room. The connection type is the same as the hose that comes from the valve cover into the oil separator, the one that is visible on the top, you need to squeeze in two sides and pull out. The Bentley manual says to slide your right hand behind the manifold and squeeze the connection and separate the line. But my hands were neither thin nor flexible enough to do that. You may be more lucky in that.

If you cannot disconnect like that, what I would recommend doing is lift the car up on the driver side, remove the engine plastic cover. Then remove the black square kind of protection plate for the gas lines. Then get a 17 mm crescent wrench and unbolt the oil return tube that goes into the engine oil pan. It has an o-ring seal on it, you may want to buy a new one from dealer.

This tube will turn freely without problem because it is connected to the oil return line but sealed with doubled up O-rings that is kept inside that oil return line connection. Once it is freed up from the oil pan, with all the other oil separator/breather lines and electrical lines disconnected and out of the way you can lift up the whole manifold.

Another option is to disconnect oil return line from the oil return tube that goes into the oil pan. For this you need a 1/2 inch automative line disconnect tool. I used a cheap plastic one from Autozone. You need to push the tool all the way in, and while it is all the way in, pull the connection apart. It may be easier done with two people, one pushes in the tool and holds it, the other pulls the manifold up at the same time which will pull the line up and disconnect.

Someone recommended to push the connection there up by placing a big flat screw driver and hitting it with a hammer, which it was reported to him the dealer mechanics are disconnected it this way.

I suggest looking and studying the related DIY articles on PelicanParts website. Search for E90 intake manifold and oil separator related DIY articles there. They have good pictures that explain. Their recommendation is to break off those oil/breather hoses and just replace with new, since they say they break off by time anyway.

It is a tedious and painful job, just because there is not enough room and all crowded in there.

Also disconnect the oil pressure switch/sensor that goes on the side of the oil filter housing, otherwise you will keep hitting the manifold to its cable and may damage it. Don't forget to plug all you disconnected
I am assuming you already disconnected the oxygen sensor cable(or cables don't remember that well) that goes through one loop of the manifold.

Removing the throttle gives more room to disconnect the junction box under the manifold, but depending on the age of the o-ring that seals the throttle body to the manifold, you may end up needing a new one once removed. Unless you don't need to, which I didn't have to, you should leave it alone.

Good luck, have patience, it is doable.

[PhaseP]

Originally Posted by Xpuzzle

I am replacing the starter in my 06 E90 325i. I have already unbolted the intake manifold and cleared all the hoses out of the way. While pulling out the manifold, saw that the oil separator was holding it back so I need to detach it. Is there a quick way to do this? Is there a screw or bolt holding it to the manifold?

Any help is appreciated.

OH by the way, I have read people have replaced alternator without completely removing the manifold. So you disconnect as much as possible that will free the manifold as much as possible, then work with the room you could gain to remove and install the alternator.
I haven't yet to replace the alternator, I had replaced the oil separator.
If I would definitely try to replace the alternator without disconnecting/connecting the oil separator there, if it is possible. It is worth trying, since the other way is not easy either.

[Volasko]

To answer OP's question: NO, you must remove entire manifold. I did a rebuild of this system a few months ago. It is a PITA of a job due to the all the little connectors and electrical lines you need to access. Also removing some of the oil and vapor lines are a bitch if you have big hands. With my car the oil return line failed clogging the oil separator, and sending large amounts of oil into my intake manifold. At one point I could hear a chugging noise coming from intake there was so much oil.

[Xpuzzle]

Hey PhaseP,

Many thanks for the help. Was able to detach the two vent hoses and the wire connectors that were holding down the manifold. It was surely a PITA with the small space to work. Putting it back was just as diff, with enough patience.

This is a great forum!

[PhaseP]