Oil Separator Info / True solution.

[amacman]

Thanks for info , I bought a spare oil filler cap nearly 2 years ago after the crank vent system failed , thinking I could fit a vent , just never got around to doing anything as yet .

[330]

We need to figure out the maximum pressure in the crankcase and add a safty margin. Does anyone know how many PSI is normal.

[amacman]

I am hunting around for the thread where I saw the info .
I think info was posted by member killcrap , a BMW tech .

edit - I checked my repair manual , only got specs for M62 TU V8 , using high sensitivity vacuum gauge the normal reading should be 10 - 15 millibar .this is vacuum at idle .
I have not yet found info on actual pressure limits .

[J.Belknap]

Originally Posted by 330

We need to figure out the maximum pressure in the crankcase and add a safty margin. Does anyone know how many PSI is normal.

http://www.jasperengines.com/pdf/BMWCrankVentSys.pdf

[X5 Meister]

Interesting write up and thanks for sharing. A few points that might be of interest as well:

1. This topic has been discussed at length on the forum and all the relevant SIB's have been posted with photos, etc. You can see that BMW has implemented fixes on all the X5 engine's and even gone as far as to cover the repairs under CPO. Here are some good references.

http://www.xoutpost.com/bmw-sav-foru...separator.html

http://www.xoutpost.com/bmw-sav-foru...-pictures.html

http://www.xoutpost.com/bmw-sav-foru...under-cpo.html

http://www.xoutpost.com/bmw-sav-foru...ed-w-pics.html


2. Every engine has a specific crankcase ventilation pressure under which it operates. It appears you are essentially negating this pressure since the engine is no longer properly 'sealed." This may/may not result in some rough running, throwing codes, etc. Just keep that in mind.

See post # 36 here:

http://www.xoutpost.com/bmw-sav-foru...-gasket-4.html

and its update in post #47 here:

http://www.xoutpost.com/bmw-sav-foru...-gasket-5.html


3. Seems like in your case the internal valve gets stuck in the closed position and then your crankcase pressure builds, and you get valve cover leak or breakage, etc. I've seen engines with a big hole in the valve cover itself and a dent on the underside of the hood from the force generated. However, should the internal valve get stuck in the open position (you've really got a 50/50 chance of one or the other happening) your fix won't help since the pressures will never build and instead you'll get an oil hydro-lock condition. Your car will stop dead and your engine will be clean as a whistle.

Originally Posted by 330

You may have misunderstood me. If you have to drive when it's zero degrees out you may want to go up one O-ring on the dip stick. The engine is still sealed just gives it a place to release high pressure in case of the catastrophic OS failure. Like a donut tire when you get a flat, it's temporary so you can continue to go. You certainly don't want to use it all the time.

Remember the newer X5 has pressure relief on the valve cover, same concept.

Although I like the suggestion about a pop off valve on the oil cap. A second oil cap could be used, fitted with a valve and put on only in extremely cold weather.

Have you guys seen the service bulletin from BMW Service Engineering about the heat wrap for the vent system which connects to your battery? Here it is but without the pictures.

SI B11 01 04
Engine
March 2004
Service Engineering
SUBJECT
Heated Wrap for Crankcase Vent System
MODEL
E53 X5 with M62 engine from start of production through 9/2003.
SITUATION
During periods of driving in extreme cold weather conditions, certain X5 vehicles may experience misfiring, blue smoke from the exhaust, high oil consumption/oil loss or engine damage.
CAUSE
Condensation in the crankcase vent system could freeze, causing higher than normal crankcase pressures. In extreme cases, this could cause engine oil to be introduced into the intake manifold and then into the combustion chambers. Should sufficient oil quantities enter the cylinders, engine damage could result.
CORRECTION
Install a heated wrap kit around the crankcase vent hoses.

[chefwong]

OT: BUT X5 Meister - glad to SEE YOU ARE BACK with some great Informative Posts. Stick around

[ncsucarjock]

330, that's some excellent advice. I don't garage my X5, and haven't been overly concerned with this issue. So far, no trouble, but I drive generally at mimimum 20 miles a day, with a lot of days being over 100 miles. So I think that mine gets hot enough on a constant enough basis to burn off whatever water is inside. Nonetheless, I do like the "pressure relief valve" idea of the dipstick. My old volvo's would spew out of the dipstick or oil cap if their system got clogged. No harm though, unless left unattended, when it would blow cam/crank seals.

If I drove less, in a colder climate, I'd probably install a "poppet" valve on the oil cap, such that at, oh, 2psi or so of pressure (recall there should be a slight vacuum at all times), it would spew excess pressure out. It'd be nice to know when it was doing this...but the oil smell through the heater should suffice, along with the burning oil as it drifts out and down onto the exhaust pipes.

Excellent short-term solution for those of us in warmer climates (though, with lows so low lately, I'm not sure I'm immune anymore)

[ernaldamerican]

the dipstick tube (going from double wall to single wall) is also part of the suggested fix by BMW. This is a crap shoot and you will have to decide how big your kahoonas are. If you have recently replaced the whole oil seperator system (say a year or two ago) than chances are letting it thaw and placing the dip stick to the last oring will be fine. As the real concern is are the lines and oil seperator not clogged when thawed. I had 113k on mine when it happened. when i took it apart my thought was that it I could have cleaned everything up and put back in, I would have saved 550 dollars. You can take the top part of the valve apart and look at the diaphragm and spring. You can clean the whole thing. The bottom half is just a swirl cage (lack of a better term) which swirls the crank case vent air/ oil and the oil drops out the bottom to dipstick and the air goes into the upper section and presses against the diaphragm / spring and than out to intake manifold. My plan is before next winter to put heat trace on the hoses and valve. Than just plug it in like a engine block heater. What evr your solution I don't think you need to replace these every year. If there was some wat to run a hose cleaner down the lines. This would ensure the lines don't have build up.

[330]

Thanks for all the feedback, you all make excellent points. NCSUCARJOCK is right about a poppet valve at 2 psi since the system will be always under vacuum from the intake. Anything over 2 PSI would indicate the engine is not breathing properly, trip the valve, and harmlessly release the engine pressure into the air. This might trip a fault code so we can tell something went wrong. As mentioned this will only help when the OS is frozen shut. If the OS fails open then it’s a different story. I would think a new upgraded OS will most likely fail closed in the cold weather. The blockage may also be in the vent tube itself, both modes would benefit from a pressure relief valve in the oil cap. I’m going to put one in and post some pics.

[amacman]

I think 2 valves would be needed .
1 for pressure relief if the system blocks . 2 PSI may be sufficient .
1 to draw air if the diaphragm fails . 50 millibar may be sufficient .