CCV and oil pressure pondering

[taosx5]

Originally Posted by JCL

To build on what twinspoppa posted, CCV refers to the crankcase ventilation system. The system includes vent lines from the valve cover, and performs the same function as a positive crankcase ventilation (PCV) valve. There is actually a valve in there, as it allows pressure to be released to the intake, while not flowing the other way at times of high manifold vacuum. BMW added an oil separator in to the system, to remove engine oil mist from the ventilation system. That is cleaner, environmentally, than burning the oil mist in the engine. The oil that is removed from the vented air flow is then returned to the oil sump. It is a fairly elegant system, except that in some models the separator is not mounted close enough to the engine to be kept warm, and it can freeze up.

There is usually condensation inside the engine due to heating/cooling cycles, but in the normal course of events it is boiled off when you drive. If the engine does not get hot enough, for a long enough period of time, that condensation will build up and eventually form an emulsified paste that collects under the valve cover. If enough of it builds up, it can collect in the crankcase ventilation system. That would still not be a huge problem, except that it has water in it, and so it can freeze if it gets cold enough out. If the valve in the CCV freezes in the closed position, then you no longer have a functioning crankcase vent, and crankcase pressure can build up. What will happen is that the pressure will push out past the weakest gasket, usually the valve cover gasket. On the other hand, if the valve freezes in the open position, then during times of high manifold vacuum oil from the sump can be drawn up into the intake manifold, potentially leading to a hydraulic lock if the oil makes it into a cylinder. That isn't common, but if it does happen, it can be catastrophic.

So, this is not related to the oiling system (except that separated oil is returned to the sump).

I don't know how similar the 4.6 is to the 4.4, and it varies slightly from year to year as well, but the principles are the same.

Thanks JCL, I sort of understood the concept but this really helps. I guees in other threads I read and pictures I had seen it must have been the older valve you mentioned because it was flat and came apart in two pieces displaying a rubber gasket that could be replaced. I wil do more reading and see if there is anyone with a similar problem on the 4.6. In my case the oil is definitely coming from the top of the oil filter cannister. I suspect that is the weakest link you describe. I appreciate your help.

I am on a road trip right now in the wife's 4.4 dealing with a mystery head lamp issue that I described in another thread. Thanks again.

[JCL]

The oil filter canister is pressurized with oil, so that isn't the same as the crankcase vent. Make sure that it is actually coming from there, and hasn't just dripped down. If it is coming from the canister, replace the seal.

[taosx5]

Originally Posted by JCL

The oil filter canister is pressurized with oil, so that isn't the same as the crankcase vent. Make sure that it is actually coming from there, and hasn't just dripped down. If it is coming from the canister, replace the seal.

JCL here is what has happended with me. Two times in the last three weeks, it has leaked oil then stopped. Both times were consistent with the very cold temps (around 0 farenheit) outside maybe around 40 degrees inside the garage. There was snow on the ground so I did not have the X5 out for a couple of days prior to these cold starts. It was in the garage. It leaked upon start up then after things warmed up and was restarted the leaking stopped. Both times it was leaking from around the top of the oil filter cannister, then stopped. It has never leaked from there before. And I last changed the filter and large rubber O-ring about 6,000 miles ago. I always changed filter when I change oil. I checked to make sure the lid was tight and not over tight. I always hand tighten it then with water pump pliers tighten it another quarter to half turn. I just changed the oil and filter a couple of days ago and after initial start up there was no leaking that I could find. The two times it leaked before it left a visible pool of oil right below the oil filter.

My theory is that there is too much pressure in the oil delivery system maybe caused by some gunk in the OS and as you mentioned blows oil out the weakest link. If it is causing it to blow it out the oil filter, to me that is better than blowing out a valve cover gasket. Is this rational thinking?

[JCL]

No. The valve cover gasket is not under pressure (inside it is just oil draining down). It isn't the oil which blows out the gasket, it is the air pressure. That is nothing to do with high oil pressure, those are two entirely different circuits.

But I don't believe you have high oil pressure. Much more likely that it is a problem with the seal on the oil filter cannister. Do not tighten it with water pump pliers. Use a torque wrench and tighten it properly. And change it every time you change the filter. It doesn't take much torque at all, and too much will just damage the O-ring.

[Ninja]

I had a similar issues with my E70 due to short trips during winter, small oil leaked if the car has not been driven for a while, took it to the dealer, they confirmed it was a faulty oil separator/CCV and replaced a new one. Hasn't had any problem since then.

3 months later, another oil leak again. Is this a common problem for all BMWs?

[taosx5]

Originally Posted by JCL

No. The valve cover gasket is not under pressure (inside it is just oil draining down). It isn't the oil which blows out the gasket, it is the air pressure. That is nothing to do with high oil pressure, those are two entirely different circuits.

But I don't believe you have high oil pressure. Much more likely that it is a problem with the seal on the oil filter cannister. Do not tighten it with water pump pliers. Use a torque wrench and tighten it properly. And change it every time you change the filter. It doesn't take much torque at all, and too much will just damage the O-ring.

Thanks JCL, do you know how want the torque setting is for the oil filter? I don't have a torque wrench so will need to get one. And I do change the seal every time I change the filter.

On another note, I did take the X5 to a Indy shop to have the OS and lines replaced. I was also experincing a small coolant leak which was evident by a burning coolant smell upon start up then go away and a small amounts of coolant residue on the skid plate. I suspected the valley pan gasket and that was confirmed yesterday. Since much of the labor would be repeated to address both issues I decided to have the OS replaced, the valve cover gaskets (which showed a little seepage), the valley pan gasket, the water pump, all coolant and vacuum hoses.

Would you recommend any other things at this time?

I was also experiencing a small steering wheel vibration upon breaking at speeds above 60 mph. It was not an issue and I suspected that the bushings on the control arms might be the culprit or possible the rotors, (after market slotted/drilled rotors). They checked the bushings which were fine. They said the front rotors are slightly warped and are checking to see if they can be turned.

Thanks

[JCL]

Mine was 25 Nm, for the drain plug and oil filter cap. If it is a V8 with a drain in the filter cover, I believe that is 10 Nm. In any case, I would check your filter cap for a torque spec, though.

Side note, but rotors don't usually warp, shops and others just call if warping. You get a deposition of pad material on the rotor as a matter of course, and if it is uneven, it produces a pulsing in the pedal. It can be very slight, but if there is any looseness in the suspension it will be enough to start the shaking. Turning the rotors gives you a new clean friction surface (if there is sufficient material there to turn them) but if the pads deposited unevenly on those rotors the first time there is nothing changing that would stop them doing it again. It is the combination of the pad characteristics, the surface finish on the rotors (modified by the drilling and slotting), and your driving habits. Just expect it to happen again.

[taosx5]

Originally Posted by JCL

Side note, but rotors don't usually warp, shops and others just call if warping. You get a deposition of pad material on the rotor as a matter of course, and if it is uneven, it produces a pulsing in the pedal. It can be very slight, but if there is any looseness in the suspension it will be enough to start the shaking. Turning the rotors gives you a new clean friction surface (if there is sufficient material there to turn them) but if the pads deposited unevenly on those rotors the first time there is nothing changing that would stop them doing it again. It is the combination of the pad characteristics, the surface finish on the rotors (modified by the drilling and slotting), and your driving habits. Just expect it to happen again.

JCL, you are a wealth of great knowledge. After lots of research I discovered the pulsing could be a number of things and only once did I learn it might be these deposits you speak of. I suspected this might be the case and have just lived with it.

I purchased this vehicle with the after market rotors and bigger Brembo brakes. I have put over 30K miles and the pads still look like new. I have never owned a vehicle with drilled/slotted rotors but if faced with having to replace rotors I would go back to stock. I am not a fan.

On my wife's X5 we have replaced the front pads twice and the rears once, and replaced rotors all the way around at about 100K. I am not hard on brakes. I have an 01 GMC 2500HD that I bought new with over 70K miles. A lot of those miles have been used to pull trailers and the break pads have never been replaced.

Thanks for your input.

[xriderob]

Hey just to share from my ccv experience in cold temps. I had several issues on cold weather start up generally -20 and below, and eventually after bringing it to the dealer and Indy found out it was ccv gunked up and they said my engine was under way to much vacuum.
Ended up getting the "updated ccv" system on the passenger side bank, driver side never an issue. Update involved moving the ccv tube/valve out from the case cover and the reason it cost over $1000 was because it required a new cover to accommodate the new set up.

New set up works better than old but still having issues. Started up yesterday morning with our first below -30 day and sure enough misfire, and I have A few days before cleaned out ccv and it was FULL of gunk. I even avoid small trips and idling. And I mean FULL With pipes fully clogged as well as the valve.

Anyways I got the p0300 (multiple misfire) as well as misfires in several cylinders. It took second to work out but after I shut off engine twice it was okay. Another bad sign and I will need to get ccv cleaned further. It sucks I spent so much on update but it still doesn't fix the flaw. As jcl always says you must adapt your driving habits or get a heated garage (never ended up getting mine finished whoops). So hope this helps and if u want more pics of update etc I can take some.
Take care

[taosx5]

I took the 4.6is in right before Xmas and after three weeks (lost ten days with the holidays) she is like brand new. I had the oil separator and hoses replaced and surprisingly ithere was not have a lot of gunk in it. The valve cover gasket was showing some seepage so I had them replace that.

The valley pan gasket was the culprit for the burned coolant smell I was experiencing upon start up. So that too was replaced. She is nine years old and has 91K miles so I decided to replace the water pump, thermostat, and all coolant hoses, and of course a coolant flush.

I was just starting to notice the seal on the differnential was begining to leak so that too was replaced.

I had lived with this slighgt wobble I would get upon hard breaking at higher speeds since I bought her three years ago. I had them mike (sp?) the rotors and sure enought they were slightly warped. There was enough metal to turn the rotors so now the wobble is gone and she runs like new.

All of this was done at an Indy shop I have been real pleased with. Total cost for all of this was $3525 including all parts and labor. I thought it best to try to replace the oil separator, valve cover gaskets, and valley pan gasket at the same time since a lot of the labor has to be repeated to do each one.

I think the price was fair. What do you all think?