M54 Oil Consumption Solved

[mcgnms]

The M54 is pretty notorious for oil consumption. Using information provided by BavarianE39 (http://www.bimmerforums.com/forum/sh...em-(Pic-Heavy) we tried doing a very similar solution and the issue has been solved. The M54 we used had approximately 1 quart of oil consumption every 2000 miles. It now has used no oil at all and crankcase vacuum seems like it has increased.

Before we go into what we did, lets first discuss how the entire system works.

During standard operation of an engine, pressure from inside of the cylinder will leak into the rest of the engine. Both crankcase and the cylinder head will experience pressure from this. If the pressure is not relieved, it becomes strong enough to blow out seals (the weakest components) and cause leaks in some areas. In this situation, the rear main seal was leaking.

E39's recycle the air as well as increase vacuum in the crankcase by using manifold vacuum to suck gases out of the crankcase. This makes for cleaner emissions and arguably better power. However, the system here is designed slightly differently because it "tries" to filter the air of oil using an oil separator.



A) Crankcase gases flow inside of the oil separator.
B) Oil drips down back to the oil sump here. The air on the other hand is sucked up.
C) "Filtered" air flows back into the intake manifold. This is also the source of the vacuum/suction.
D) Contains a small hole control to allow for proper control of the spring loaded valve that helps control the suction.

An inherent failure point is when (A) develops green goo and freezes the inlet. This results in crank case ventilation being blocked. The other problem is that (B) goes into the oil sump below the oil level so if (A) is blocked, then oil will be sucked up through (B) and get dumped into the manifold potentially causing a hydrolock from oil. This exact issue happened to me. Luckily however, the engine was not damaged. My fix for this at the time of occurrence was using airbox suction where it is weaker than manifold suction to prevent the risk of hydrolock. I have seen other solutions where a somewhere in the pipe between (B) and the oil sump, a hole is created to prevent a vacuum should (A) once again...become frozen and blocked.

An interesting note. The M62 and S62 have a similar design and operation to the M54. The minor difference is that the oil separator and the valve are in different places connected by a pipe. The oil separators on S62's and M62's sit in the front of the engine. The KEY difference is that the bottom of the separators are not below on an oil level. A blockage of the inlet will NOT cause an oil based hydrolock making is arguably safer. Why the drainage is below the oil level on M54's, I do not know.





We opened the housing and here is what is located inside. This shows the oil separator itself.



Here is the entire system. The orange circle is the actual "CCV" valve/flap that helps control the vacuum. It has a spring on one side with a tiny hole into the atmosphere on the other side.





Below is the temporary solution used. It is a simple PCV valve system without any oil separator. The crankcase is connected directly to the manifold with a PCV valve in the middle. It will be slightly redesigned for permanent use soon:











So why has oil consumption stopped? I do not know for sure. Perhaps higher crankcase vacuum? Perhaps the oil separator always sucked a slow/steady stream of oil through the opening (B)? It is difficult to know for sure. One thing is for sure...this system somehow caused it and its elimination/re-design has solved it.

[carlova789]

Yup, I need to do my ccv again.

[auaq]

I do 7k oil change and I drain about 5qts of oil, so pretty satisfied at 198k mi. CCV was already replaced long time ago. However, if I do end up having to replace it one more I might eventually go this similar route one day.

[BavarianE39]

Woohoo, another success story. Mine is still going strong, not a drop of oil burnt, engine runs top notch, and if I ever need to replace this PCV valve its like $5 and a 5 minute job.

[Jason5driver]

mcgmns,
When you refer to "We", are you referring to a shop or vendor?
Also, what Pcv valve did you use?
The same as Bavarian's?
Thanks!
Jason

[mcgnms]

Jason5driver, by we I am referring to my dad and I. He has an E53 X5 with the same M54 that us good old E39's do. I am not fully sure what the exact valve was, but I will get you this information. Certainly, if I wanted to put the time investment in, I can probably figure out what the original cause was. Install transparent tubing, vacuum gauges in the crank case and manifold, and monitor where the oil is going.

[philly98540]

Great fix for the HO6 guys! Seems so damn simple, it really makes you wonder why BMW did all the extra cr@p that has the potential for doom. Did they really overlook having the drainback below the oil level? Seems downright criminal almost.

I wonder if the lower oil consumption is related to no longer sucking up oil from the pan, or is it due to different crankcase pressures? Maybe those low tension rings are working better now with better crankcase vacuum?

[Jason5driver]

Jason5driver, by we I am referring to my dad and I. He has an E53 X5 with the same M54 that us good old E39's do.
I am not fully sure what the exact valve was, but I will get you this information.
Certainly, if I wanted to put the time investment in, I can probably figure out what the original cause was.
Install transparent tubing, vacuum gauges in the crank case and manifold, and monitor where the oil is going.

Thanks.
Were you able to stop the rear main seal leak?

Also, the thing that bothers me about this modification, is that there is no filter from the engine head/crankcase to the intake, other than the pcv.
Condensation is still being sent to the intake unfortunately.
And, the original Pcv that Bavarian used was giving too much vacuum to the system IMO.
It was evident when trying to remove the oil dipstick after the car had been running.
It was like the slirpy-monster was hiding out in the oil dipstick.

[cnn]

Jason,

Don't worry about condensation, it will be burned in the combustion chamber.

In fact, this mod brings back the simple CCV design of E23 (1983-1987 735i) setup.

[BavarianE39]

Yes Jason, you're right that this does cause higher than normal crankcase vacuum and there could still be condensation much like in the original CCV, but what this mod does provide is a bit of confidence that the system wont freeze over and gulp oil from the oil pan which could potentially cause a hydrolock. I've been working in a shop that does lots of BMW-Audi-Mercedes repairs and this something that I have seen more than once on these engines.

[mcgnms]

Thanks.
Were you able to stop the rear main seal leak?

Yes we were. I think that is evidence of more vacuum in the crankcase.

Also, the thing that bothers me about this modification, is that there is no filter from the engine head/crankcase to the intake, other than the pcv.
Condensation is still being sent to the intake unfortunately.
And, the original Pcv that Bavarian used was giving too much vacuum to the system IMO.
It was evident when trying to remove the oil dipstick after the car had been running.
It was like the slirpy-monster was hiding out in the oil dipstick.

There may not be a filter, but the stock system can hardly be considered a filter either. A certain amount of crankcase vacuum is desirable though the real desired value is difficult to say in this situation.

Yes Jason, you're right that this does cause higher than normal crankcase vacuum and there could still be condensation much like in the original CCV, but what this mod does provide is a bit of confidence that the system wont freeze over and gulp oil from the oil pan which could potentially cause a hydrolock. I've been working in a shop that does lots of BMW-Audi-Mercedes repairs and this something that I have seen more than once on these engines.

It does. I had a hydrolock on my M54 from this exact issue. It makes an M54 rather terrifying to drive on short trips during sub freezing weather.

[syphilouis]

Being that I have to wait all day tomorrow to drive my car for rtv to dry fully, I may do this mod. Did you use the pcv from the other thread mentioned?

[cnn]

O.P.,

Could you post the source where you buy the generic PCV valve a PEX fitting sizes?
For now I am taking your photo and put some arrows on it for discussion...

[Poolman]

No different than than the oil catch can that a few of use have built,,the main part is the PVC valve which allows full vacuum to the crank case. The oil catch can, will catch the condenced oil before it goes back into the intake manifold. This has been around the block before. Good to see that it's working for others. Check the link out and read to the end

http://www.bimmerfest.com/forums/sho...d.php?t=601440

[mcgnms]

Being that I have to wait all day tomorrow to drive my car for rtv to dry fully, I may do this mod. Did you use the pcv from the other thread mentioned?

We did use the exact same PCV valve as Bavarian did. Same part number.

Stuff was bought in Autozone/Home Depot.

Also, yes that hose "Leaves Open to Air" will get left open. The housing of the CCV/Separator is no longer in use or connected anywhere. You can remove the entire assembly if you would like.

[blk90s13]

very interesting results.

[RBNetEngr]

I am also dealing with a high oil consumption issue (2003 E39 525i), and was preparing to replace the CCV system to see if it fixes the issue.

While the simplicity of this PCV system modification is ok, I was wondering how it affects the operation of the engine CCV. After all, on vehicles with a simple PCV valve system, the PCV valve is designed to allow a specific ventilation flow for the system, based on the size of the valve and lines, as well as the spring tension of the valve. Choosing a PCV valve based on physical size alone means there's still a range of spring tensions, and thus flow rates, through the valve itself. I don't know if this is critical or not, but I'm just asking if anyone looked at this issue.

As a possible alternative, has anyone looked at using the CCV system from the M52 engine on the M54?

From realoem.com:

M54 CCV (looks like a nest of snakes!):
http://www.realoem.com/bmw/enUS/show...diagId=11_2194

M52 CCV:
http://www.realoem.com/bmw/enUS/show...diagId=11_6076

I don't recall seeing anyone mention trying this out on the M54. I'm sure it would take some work with hoses and fittings to get it connected properly.

Another interesting (to me) point about CCV, is the simple system that was used on the M50/S50 engine.

From realoem.com (S50, for 1 1995 M3):
http://www.realoem.com/bmw/enUS/showparts?id=BF93-USA-10-1994-E36-BMW-M3&diagId=11_1284


In this case, there isn't even a CCV separator, just some hoses and reducers. Now, clearly, the CCV system has been evolving into something more complex as each generation of engine is developed, but does it really help?

-rb

[JaxPlanet]

Does anyone know if the m52tu has this problem?

[Jason5driver]

I am also dealing with a high oil consumption issue (2003 E39 525i), and was preparing to replace the CCV system to see if it fixes the issue.

While the simplicity of this PCV system modification is ok, I was wondering how it affects the operation of the engine CCV. After all, on vehicles with a simple PCV valve system, the PCV valve is designed to allow a specific ventilation flow for the system, based on the size of the valve and lines, as well as the spring tension of the valve. Choosing a PCV valve based on physical size alone means there's still a range of spring tensions, and thus flow rates, through the valve itself. I don't know if this is critical or not, but I'm just asking if anyone looked at this issue.

As a possible alternative, has anyone looked at using the CCV system from the M52 engine on the M54?

From realoem.com:

M54 CCV (looks like a nest of snakes!):
http://www.realoem.com/bmw/enUS/show...diagId=11_2194

M52 CCV:
http://www.realoem.com/bmw/enUS/show...diagId=11_6076

I don't recall seeing anyone mention trying this out on the M54. I'm sure it would take some work with hoses and fittings to get it connected properly.

Another interesting (to me) point about CCV, is the simple system that was used on the M50/S50 engine.

From realoem.com (S50, for 1 1995 M3):
http://www.realoem.com/bmw/enUS/showparts?id=BF93-USA-10-1994-E36-BMW-M3&diagId=11_1284


In this case, there isn't even a CCV separator, just some hoses and reducers. Now, clearly, the CCV system has been evolving into something more complex as each generation of engine is developed, but does it really help?

-rb

Great Post...!

I have brought up / thought installing the S50 system.
However, one hose in that system connects to the throttle body, and the other to the ICV I believe.

[16valex]

I don't believe this mod totally solved the oil consumption. I believe it helps. In my case 50% reduction, that's very good though.

I want to hear some new reports.

[m735is]

JaxPlanet: I do not think the m52TU has the oil consumption problem. I think it's on the m54 due to the piston rings. My 99 528i has 183,000 miles on it and does not use any oil between my 4-5,000 mile changes. Having said that I MAY use a similar system on it if the CCV starts to fail. Other posts show the PCV valve installed, basically the same setup as above.

[jstern]

I have 3 E39s all with the M52TU with 240K, 95K and 56K. None of them use any oil ever. They have all gotten regular oil changes with M1 throughout.

[cnn]

I don't believe this mod totally solved the oil consumption. I believe it helps. In my case 50% reduction, that's very good though.

I want to hear some new reports.

I agree.

I have a 1998 528i M52 with 160K, zero oil consumptions. All CCV etc. up to date.

My 2006 X5 M54 drinks about 1 qt/1,000 miles-1,500 miles or so. CCV also up to date.

I believe it is a combination of CCV issues and low-tension piston rings. Over bimmerfest E39 forum, I am waiting for poolman's update on the AC Delco top end cleaner report. This is the stuff that is supposed to clean the sticky piston rings.

[16valex]

I agree.

I have a 1998 528i M52 with 160K, zero oil consumptions. All CCV etc. up to date.

My 2006 X5 M54 drinks about 1 qt/1,000 miles-1,500 miles or so. CCV also up to date.

I believe it is a combination of CCV issues and low-tension piston rings. Over bimmerfest E39 forum, I am waiting for poolman's update on the AC Delco top end cleaner report. This is the stuff that is supposed to clean the sticky piston rings.

Yeah, I've been watching that too. I may give Poolman's ACDelco a try pending on his results.

My 330XI used to drink a quart per 500 miles but with this mod it reduces the consumption by 50%.

[FastGpa]

We did use the exact same PCV valve as Bavarian did. Same part number.

Stuff was bought in Autozone/Home Depot.

Also, yes that hose "Leaves Open to Air" will get left open. The housing of the CCV/Separator is no longer in use or connected anywhere. You can remove the entire assembly if you would like.

I just completed this...tho I capped my dip-stick tube from the CCV. I had noticed a few months ago that the plastic accordian tube that attached to the 90 that comes out of the valve cover was cracked and had been repaired with electrical tape. Really easy following the dimensions above. I used a PCV valve from a Ford 3L...so I'm thinking it should flow enough for the M54. Started her up...no leaks and no hissing. Very satisfied.