DIY Oil Separator Replacement 4.4
 

Just finished replacing the oil separator in my "02 X5....Took about 3 hours.

Started having rough idle problems and after removing the top cover on the intake manifold I was horrified to see a hose near the rear of the intake manifold that actually had a hole in it. It actually was like jelly all soft and mushy. After reading on the forums here I discovered it was the oil separator line.

So here how I did it.

Remove the top engine cover (four hex head screws)
Remove the rear bracket that the top cover attaches to (two 10 mil bolts)
this makes it easier to get your hands back there to work

Remove the gaskets around the fresh air intake for the cabin they are just pressed into place and easily remove.

Remove the cabin fresh air intake (two 13 mil bolts.)

Undo the clips which hold down the cowl screen & lift the screen out

There are 2 side ducts under the screen which attach to the cabin fresh air intake. Lift them straight up. A little wiggle & they should come right out.

Once those are removed you can pull the cabin air intake toward the front of the vehicle. Be careful around the washer fluid bottle when you remove it.

OK Finally now you can work on the oil separator & the lines.


There are 3 lines you need to change Plus since youare in there change the separator also... List pricefor it is about 40 bucks

The separator is attached near the rear of the intake manifold on the passenger side and is held in place by two 10 mil bolts. it has 2 3/4 rubber hoses going into it and one small 3/8 hose on the bottom which you really cant see until you remove the bolts and start to lift the separator out.

I used a razor and cut the 2 mushy 3/4 hoses off the separator. I unbolted the separator and cut the 3/8 hose off the bottom. There are 2 hose clamps attaching the other ends of the 3/4 hoses one on the drivers side valve cover the other to a port just below the valve cover.

Now the hardest part. the remaining line the 3/8 hose you need to just about stand on your head to remove it from the metal line it attaches to. There is a bracket which attaches this line to the rear of the engine. I removed the bolt from the bracket, and was able to move the line over about an inch to get the clamp and remaining piece of hose off. Whew!

Ok grab something to drink, stare at everything and say what the hell was BMW thinking when they designed this...


Reassembly isnt too bad....

I bought 3 feet of 3/4 heater hose & 1 foot of 3/8 fuel hose & some new clamps.. 11 bucks. BMW wants 75 bucks for the oem hoses...


I started by attaching the 3/8 line to the oil separator, clamping it the sliding the hose down between the rear to the oil line. I think the length of the 3/8 hose i used was about 7 inches. slid the hose over the oil line & tightend the clamp. Make sure the 3/8 line does not have any kinks. It is an oil return line and you want the oil to be able to drain.

Reattach the new oil separator to the bracket with the 10 mil bolts.

Get the 3/4 heater hose and attach it to the valve cover port tighten clamp and carefully route it to the separator. It attaches to the bottom port. Make sure the line doesnt rub against anything or have any kinks in it. Cut it to length clamp it.

Attach the remaining 3/4 hose to the valve to the port located just below the valve cover carefully route it to the top port on the separator. check for kinks rubbing ect, cut to length and clamp.

You've just changed you Oil Separator and saved yourself a bundle of money.

Now reinstall the cabin air intake, top cover rear bracket, cowl covers gaskets and engine top cover and your done.


Just a quick note,,, make sure there is no sludge or buildup on the ports the hoses attach to. Also I have to basically crawl into the engine compartment to do this. If your a big guy or girl.....probably aint gonna happen


Lastly only do this if your comfortable working on cars... I am not responsible if you blow up, burn down, scratch, break ... or otherwise do something your unhappy about to your BMW.

cheers!

do you have any pictures of where the oil seprator is located on the engine and the hoses

i'm at the point where I am having an alcoholic drink and standing back and thinking...What the hell was bmw thinking? tomorrow i will tackle the oil seperator installation. what a job this is. i'm going to bed

Yesterday I installed the oil air (oil breather) separator on a 2001, 3.0. Definitely not a fun task. I just wanted to comment on the note which mentions that you put the uppper hose on the separator first. After struggling with this suggestion for a decent amount of time, I called the dealer and they were nice enough to help over the phone. The factory procedure is to first mount the separator in place with two coarse thread torx fasteners. What I suggest doing even before this is to fish the upper tube through the first and second runners until it aligns in properly in the below "slot" adjacent to where it would connect to the separator. Using a mirror helps. With the separator mounted and the upper hose aligned to the separator, rotate the upper hose (parallel the crankshaft axis) 90 degrees towards the passenger side. Push the hose towards the rear of the engine until it mates snugly against the separator. Now rotate the hose (from the top side of the engine) 90 degrees towards drivers side. Practicing with the hose and separator off the car will give a clearer idea. Lower hose: fish it from the top (by the power steering pump reservior) and attach it to the separator first. Then fasten the top connector.

did you have any problems with the hoses not being molded? Did you get any kinks in the lines where you had to bend the hoses?

It sounds like I'm having a similar problem. Last year I noticed an oil leak and had my X towed to a local shop that specializes in BMWs. They mention that they could not find the leak but suspect that it's an oil release valve and to keep an eye on it. Luckily it never happened again.

We have been getting extremely cold weather in Manitoba (Canada) -30C to -35C (-22F to -31F) the past couple of days and sure enough I found another puddle when I pulled out of the garage today. I typically only drive 15min or so to work so I imagine that this is not long enough to let the condensation to burn off.

Will replacing the oil seperator do anything in my case? What other preventative measures can I take to ensure this doest keep happening?

On a side note I don't have a block heater and BMW doesn't make one for my X5 (2004 4.4). The shop that I normally take my truck to said that I can install a oil pan heater but it has it's advantages and disadvantages. Whats are your throughts on this?

Thank you (from an extreamly cold X5 owner)

oil sep hoses
 

I had no problem with kinks in the hose, there is plenty or room to make gradual bends to line up the hoses

Mine was done on a 4.4 It may be different for a 3.0

Going to bump this topic up to the top again.

I had every intention of replacing my O.S./CVV this weekend but didn't plan on pulling the intake manifold as I've heard that's the way the techs do it and most other DIY'ers have done it as well. There's just something unnerving about pulling the fuel rail...

Anyway, I pulled the air intake snorkel all the way to the manifold out. This included removing the DISA and ICV. Even after this procedure, I still could not see the oil separator. I'm guessing it's somewhere below the throttle body but the throttle body itself was barely in sight.

How do you 3.0 guys do it??

Well, you are about halfway there. :thumbup:

It is actually adjacent to the TB, on the left side of it looking at the driver's side of the engine from the front quarter panel.

With the air intake stuff out of the way, you will be staring at a gray box bolted to the underside of the intake manifold. It has wires going in and out of it - they go to sensors. Unbolt that and push it aside. You will most likely need to disconnect the sensor connection at the adjuster unit (black butterfly stuck in the intake manifold) to do this, and maybe one or two more. Don't worry, they all only logically reach what they are supposed to go on, so you can get them back on.

With that out of the way, you should be able to see the bottom of the separator. Don't get too excited. To actually dismount the thing from it's hidey hole, you need to pull the throttlebody off. There are 4 bolts, and you more than likely removed one already to get the little gray wire box off - they share one bolt. Once you pull the TB off, you can get the second screw off that holds the separator to the underside of the intake manifold. Really, you could bust the separator in half and get it out before you pull the TB, but you can never gain access to the second screw until you get the TB off; no tool I know of can under a screw in that little space. You will see what I mean when you find the separator.