Could it be going through the CCV and into the intake and being burned? Just shooting from the hip here, not sure if it makes sense.

 

That is a common failure mode of the CCV, but this one is brand new, and the problem pre-dated its replacement. The CCV is condensing oil vapors, and returning the oil to the crankcase. In just a few hundred miles, I can't believe it would even SEE almost two quarts of oil.

Regards,
Ray L.

 

Piston rings?

 

But if so, how is the compression so high? And, hos does it go long periods using NO oil, then suddenly gulp down a quart or more in a relatively few miles?

It occurs to me this behavior started years ago, when it had an unfortunate incident involving a large rock on the road. The rock took out the engine and transmission oil pans, the oil pump pickup tube, the front cross member and chassis stiffener, and some other stuff. It was after that repair that I first saw it suddenly lose a lot a oil in a short time, and I've never been able to figure out how/why.

Regards,
Ray L.

 

need new rings. oil is simply not scraping down and getting burnt slowly. compression #s are based on instantaneous bursts. not enough leakage in rings to show but enough to be slowly consumed. just a reality with many high mileage BMW engines.

 

I think it is the oil rings, although I can't explain why clogged oil rings - which I think would lead to oil slipping past all three rings and into the combustion chamber - wouldn't reduce compression.

I am not familiar enough with M54 oil lubrication, but I've seen non-BMW comments that indicate clogged oil rings lead to too much oil in the crankcase and that excess oil is somehow sprayed into the combustion chamber, again which I don't understand.

There are other posts on this with pictures, but the M54 engine originally came with an oil ring design that had drain holes which were too small, and clogged easily. Mahle (OEM supplier) quietly upgraded the design at some point with longer slits that drain better. It's unclear if, or when, the upgraded design ever made it in to production. But if you buy Mahle M54 rings today, you will get oil rings with bigger slits. I have pulled the original rings from a couple of M54's and they were indeed fully clogged.

Several folks have reported the M54 oil consumption goes away after replacing the rings. I can't myself say this as I haven't yet installed the engine I replaced the rings on.

Regardless, if oil is entering chamber you should see evidence of oil burning on the plugs.

It sounded like your head gasket job went very well, and with how I believe you reinstalled the head, there is little chance you gouged the block or head. Has this oil issue changed at all since you replaced the head gasket or is it the same as before?

 

it seems to go a long time barely using any oil, then suddenly disappears a quart or more in no time at all.

This strongly suggests CCV malfunction. The CCV dump back down the dipstick tube (STUPID!) is within 1/2" of the average
'full' level for the car. If you pull your dipstick with oil in the pan, it's right there.
So if the CCV malfunctions and starts sucking (worse than usual)
it will be able to pick up oil whenever you decide to turn right, even gently.
It gets worse if the oil dump is partially clogged, which doesn't take much.

It can also fail intermittently.

Pretty easy to rule this out (lots of ways, take your pick).

Both our cars started using oil this way, and replacing CCV valves and components reduced it significantly. As did using Shell oil vs Mobil 1.

2 anecdotes, and some plumbing,
t

 

This strongly suggests CCV malfunction. The CCV dump back down the dipstick tube (STUPID!) is within 1/2" of the average

+1. If the rings are worn down or clogged, the engine will burn oil more or less at a constant rate.

OP, have you noticed higher than average accumulation of soot on the tailpipes during the periods your car is "disappearing" oil?

 

The top two rings are primarily the ones that hold compression. The third, lower ring set scrapes the oil from the cylinder wall.

It's the lower ring set (a one-piece ring with a helical wound backer) that becomes clogged. That leaves it unable to remove the bulk of oil from cylinder wall, and the oil then overwhelms the compression rings. You can't detect that clogging with a leak-down or compression test. If anything, the compression will be slightly better.

 

100% you have no oil leaks? Not even oil pan gasket?

 

100%. NO leaks. No oil, no coolant, trans fluid, no P/S fluid, no anything.

Regards,
Ray L.

 

If you recently swapped CCV and after that you are losing engine oil, i recommend that you read 02pilot mod diy thread.

 

"Wohin geht mein Öl?". That was the chant in BMW's research labs when they tested the M54 engine. They couldn't figure it out either. Too far down the line to fix it though. That's why they added an oil level sensor instead. To give you a fighting chance of avoiding engine seizure every 1000 miles.

 

Up in smoke, I was burning a quart every 300 miles for 3 years from 122k to 155k every fill up of gas got a quart dumped in until.

I refreshed my steering linkages and front bushings w control arms 10 pieces. Now it stopped burning oil and I just hit 175k in the 05 325xit

 

Believe me. There is absolutely NO causal relationship between steering and oil consumption.

 

Ray, you said your dipstick tube and the oil return part of it were clean. Just checking to see that you cleaned it 'down' through the oil return port so the interior of the double wall space is clean.

Your issue does sound like CCV, so before you eliminate that as an issue entirely, I thought I'd annoy you!

 

Yes, the oil return port in the dipstick tube is completely clear and clean.

So how does one "test" the CCV?

Regards,
Ray L.

 

I am just watching a video on direct injection vs port injection pros and cons. The last few minutes talks about NOACK Evaporation Loss. Basically, oil evaporates. That's it. 0W oil evaporates more than 5W oil and 5W more than 10W. Thinner 0W oils have a higher volatility rate usually above 7%. I don't know what oil you are using but if it's 0W maybe you could go up to 5W. Might reduce consumption a bit. My handbook specifies 5W 30 or 5W 40 oils as being suitable. I have used 5W since I bought this car without any issues. I don't know whether a move eo 10W would be ok. Perhaps in warm climates. Probably nota good idea in really cold climates.

 

If this problem has been ongoing then the only logical conclusion is that the oil control rings and/or oil drain holes in the bottom rings’ groves are clogged.

A few questions:
- what is the typical oil change interval?
- what oil are you putting in the engine?
- how is the car driven? Short trips?
- have you tried the 02pilot mod?
- have you checked for vacuum at the oil fill cap?
- have you looked into the GM Top End Cleaner treatment?

 

Simple way to determine if the crankcase has the typical vacuum is to set up an OBDII scan tool with Live data and watch the Fuel Trims while the engine is at warm idle. Then remove the oil fill cap with the engine idling and the STFT should immediately jump around 20-24% and typically max out at around +27%. \

If you are consuming oil at the rate you indicate, I would expect your catalytic converters may suffer soon. What oil are you current running? I would probably change to a different oil and also make 100% sure the plastic end of the dipstick is not loose on the dipstick wire giving you a false reading.

Also smell the oil and make sure there is not a high amount of fuel in the crankcase.

As mentioned the oil rings can be problems on these engines, some have performed tear downs and found the oil ring and sometimes the piston ring end gaps were way too large and some have found the oil ring expander was overlapped and not providing enough tension for the oil control ring. And lastly some have found the oil drain holes and expander tend to be carboned up again from long oil change intervals, defective CCV and large end gaps on the compression rings allowing combustion gases and by products to work their way to the oil control rings.

I have also found restricted exhaust can cause more oil consumption as well, typically restricted exhaust has other side effects and is consistent, however, if the car is driving in town mostly but then the oil consumption goes up on the highway at higher sustained RPM, then the exhaust back pressure should possibly be tested.

There was a member here by the name of mlody that did a lot of research into the oil consumption issue and finally tore down and rebuilt his engine. I recall the piston rings were a problem, both compression and oil control. For some reason he was either banned and/or he removed all of his posts. You might be able to find some useful info in some of his YouTube videos - https://www.youtube.com/user/mlodydark/videos

 

From post #26 above:

also make 100% sure the plastic end of the dipstick is not loose on the dipstick wire giving you a false reading.

Remove the dipstick and grasp the plastic bottom of the dipstick and see if it is loose and/or turns on the dipstick wire, if it does, it can and will give bad readings and the dipstick will need to be replaced, but beware some of the replacement dipsticks require a new guide tube installed due to different lengths.

 

I am very interested in this thread as I'm buying a 2002 with 140k very well cared for miles. Elderly owner reports it "uses oil" and the mechanic has not figured out why. I brought it to my house to inspect it and the exhaust has that exact (nice description Ray L.) "laser printer toner" stuff in the exhaust tips and indeed while I had it running in my garage to see if I could find any active leaks it sputtered some of it onto the ground in a spray pattern. I was holding the car at 3k RPM at times to get high oil pressure and condensation and that created the pattern. The rear of the car has a faint coating in the form of pinhead size speckles I believe to be that stuff.

So, I'll soon be also working this from my end. If its indeed an oil ring issue this car would be a candidate. The car was used to putter around town by two elderly folks and probably has a carbon buildup issue just in general. So if the engine is prone to it, this would be something to pursue. I've never been a "use seafoam to clean carbon up" kinda guy but this may cause me to reconsider if I can accomplish something with it. Dunno. Perhaps just a nice long run on the freeway.

Thanks in advance for the continued thoughts and input.
Doug

 

When I first bought mine I contacted BMW about the oil consumption because the seller told me that a liter per 1000 Km was normal. BMW confirmed as much. I have never had a car that used any oil between scheduled oil changes so I was a bit pi55ed at the news. I had a 2L E36 before my E46 and a 1.6L E36 before that and never used a drop. It is something you have to learn to live with and manage. I have used Seafoam in my oil 100 miles before changing the oil and filter. I can recommend it. I did't take it out and rag it with the Seafoam. I just did my ordinary driving and let the additive do its job.

 

This is odd.... So, I wiped off the dip stick, jammed it back in, and the oil level is exactly at full. The coolant was low, but only about a pint, or less.

So, what would cause the ridiculously high initial reading on the dipstick? Is it not extended well beyond the end of the tube, down into the sump? There was such a massive amount of oil on the plastic lower end of the dip stick, it's almost like a large quantity of oil got dumped on it AS it was being pulled out. If simply suspended for a few seconds much of that oil would have simply dripped off. So, how is it possible for there to have been so much oil there? I can only come up with one theory, but it makes absolutely no sense to me: There was a partial vacuum in the crankcase when the engine was shut off. Let's make the (ridiculous) assumption that the crankcase is really well sealed, so that vacuum was actually maintained over-night. The oil separated out by the CCV accumulated in the return path of the dipstick tube, and simply sat there. When I pulled out the dipstick, the vacuum was released, and the oil in the return path of the dipstick tube was released, and dumped on the end of the dipstick, before it got above the bottom of the tube. That seems to me incredibly implausible, but is the only explanation I can come up with.

This is becoming quite perplexing...

I re-checked the crankcase pressure, and, sure enough, there is a slight vacuum - probably a few PSI below ambient, which seems right to me. It is definitely nothing even close to manifold vacuum, but well below ambient, so I believe it is in the right ballpark. That would tend to disprove a problem with at least the pressure regulator portion of the CCV. The other parts are all passive - just the "cyclone" separator, and a bunch of pipes and hoses.

I see much greater crankcase vacuum in my E90 335i, but that has a completely different vent system, and has two turbos to deal with. That engine, with 106K miles on it, uses a quart of oil only every 5K miles.

Regards,
Ray L.

 

I re-checked the crankcase pressure, and, sure enough, there is a slight vacuum - probably a few PSI below ambient , which seems right to me. It is definitely nothing even close to manifold vacuum, but well below ambient, so I believe it is in the right ballpark. That would tend to disprove a problem with at least the pressure regulator portion of the CCV. The other parts are all passive - just the "cyclone" separator, and a bunch of pipes and hoses.

I see much greater crankcase vacuum in my E90 335i, but that has a completely different vent system, and has two turbos to deal with. That engine, with 106K miles on it, uses a quart of oil only every 5K miles.

Regards,
Ray L.

The crankcase vacuum at idle with stock, properly working CCV system should be much lower, about 0.2 PSI negative pressure. A "few PSI below ambient" sound more like the vacuum is too high, not too low...

 

Whups, we typed over each other-

sounds to me like your dipstick tube is filling with oil.
That's something the CCV can do by sucking on it- if it's failed.

I have had aftermarket CCVs that were defective right out of the box.

hth
t

And those easy ways would be..... what?

Run its drain to a catch can, plug the dipstick drain.

Make a 'vacuum breaker' arrangement in the existing drain.

Add the M3 separator.

Try the M56 valve cover.

...for starters.
There are lotsa threads I've browsed here over the years-
so searching for CCV and catch can and so forth might work.

My personal theory is that the stock CCV is marginal,
it's trying to perform a pretty sensitive task in a small space
with limited resources, and that aftermarket ones are usually not right.
AND as they age, they also go 'not right' as the soft components harden.

IF the darned thing was easy to get to, I suspect we'd have figured
out a good fix long ago.
SINCE it's such a turd to work on, it's been a booger to get right.
I know I hate going in there to try to modify anything...

fwiw,
t

 

sounds to me like your dipstick tube is filling with oil.
That's something the CCV can do by sucking on it- if it's failed.

Yes, it does look that way. But this is the first time I've seen this happen...

Run its drain to a catch can, plug the dipstick drain.

I assume you mean plug the end of the dipstick tube the CCV drain normally connects to?

Make a 'vacuum breaker' arrangement in the existing drain.

No comprende. How?

Doesn't the above mess with the crankcase pressure, which will mess with mixture? When I remove the oil filler cap, the engine runs rougher. Seems to me diverting the CCV drain to a catch can will do the same.

Regards,
Ray L.

 

No, the crankcase vacuum is almost always much lower than the intake vacuum. I was also talking about relative negative pressure (to the ambient, atmospheric pressure).

 

Let's get on the same page - If I attach an absolute pressure gauge to the oil filler hole on the valve cover, with the engine off, it will read ~14.7PSI. If I then start the engine, I would guess that will drop to something on the order of 13PSI. If I connect that same gauge to the intake manifold, with the engine idling, I would expect to read something on the order of 5PSI, if not less.

If I do the same with a vacuum gauge that reads in mm-Hg, with the engine off the crankcase will measure 0 mm-HG. If I then start the engine, I would expect to see that change to ~2-4 mm-Hg. I would expect the intake manifold, at idle, to read 18-22 mm-Hg.

Can we agree to that much?

A "heavy" vacuum in the crankcase is a sure-fire sign of a failed CCV - it indicates the pressure regulator has failed open, and is delivering full manifold vacuum to the crankcase.

Regards,
Ray L.

 

Hope this is additive but when I had this E46 in my garage looking at it and running, I did release the oil filler cap to a faint hiss and expected slight change in engine tone as the cap's seal released. Hmmm..

 

^normal.

 

We use 600 millibar as our change engine marker. Atmosphere is 1000 millibar at sea level and normal crankcase pressure running on track would be in the 300-400 millibar range. Once it shows 600 or over we know that the engine worn and failure is imminent.

 

I think this is getting is getting all out of hand.

Start the engine and while it is running can you remove the oil fill cap? If so, chances are the crankcase vacuum is NOT too high. Usually if the crankcase vacuum is too high, you cannot remove the oil fill cap with the engine running.

Get an OBDII tool, set it up to monitor both the Long and Short Term Fuel Trim values. While the engine is warm and idling, remove the oil fill cap and watch the Fuel Trim values, the STFT should shot up immediate by about 20%, might max out around 27%. LTFT should not change, this is how a "normal/good" engine functions.

If you start trying to measure the crankcase vacuum, I do not believe there is a spec for this and will likely get all kind of wrong and inaccurate comparison data. I mean you are already off the tracks with the mm/Hg you are stating in Post #47. You stated intake manifold vacuum should be 18-22 mm-Hg. 22 mm-Hg is ONLY 0.866145 in-Hg. Intake vacuum should typically be the range of 18-22 in-Hg! But this is a range, some engines have less intake vacuum depending on a lot of different factors. So make sure you have your Units correct.

Sounds like you should check the oil the proper way. Drive the car and warm it up, shut the engine down and remove the dipstick and wipe if off, reinsert the dipstick and check the oil level. IF you have been adding a lot of oil lately, you may need to drain the oil, measure it and only add 6.5 quarts back in the sump, you can run the current oil though a paint filter. Then check the oil the proper way and keep an eye on the level over the next 4 tanks of fuel.

 

I think this is getting is getting all out of hand.

Start the engine and while it is running can you remove the oil fill cap? If so, chances are the crankcase vacuum is NOT too high. Usually if the crankcase vacuum is too high, you cannot remove the oil fill cap with the engine running.

Yes, I can easily remove the cap while the engine is running, and when I lift it off the valve cover I feel it being pulled down until the seal breaks. As I said, the pressure differential feels to me like a very few PSI, like 1-2.

Get an OBDII tool, set it up to monitor both the Long and Short Term Fuel Trim values. While the engine is warm and idling, remove the oil fill cap and watch the Fuel Trim values, the STFT should shot up immediate by about 20%, might max out around 27%. LTFT should not change, this is how a "normal/good" engine functions.

I have a Foxwell NT510. Not sure if it shows those STFT and LTFT. I'll have to explore the menus a bit more and see. There is a minor, but very obvious difference in the way the engine idles when the filler cap is removed, so I will be surprised if I do not see the kind of readings you describe.

If you start trying to measure the crankcase vacuum, I do not believe there is a spec for this and will likely get all kind of wrong and inaccurate comparison data. I mean you are already off the tracks with the mm/Hg you are stating in Post #47. You stated intake manifold vacuum should be 18-22 mm-Hg. 22 mm-Hg is ONLY 0.866145 in-Hg. Intake vacuum should typically be the range of 18-22 in-Hg! But this is a range, some engines have less intake vacuum depending on a lot of different factors. So make sure you have your Units correct.

Sorry, typo. Those numbers were in-Hg, not mm-Hg. There actually is a spec, but it's not in the service manual. Dealers have it. I know because I had a talk with a BMW dealer diagnostician, and he knew the number spec range off. Unfortunately, that was a while ago, and I don't remember what the numbers were.

Sounds like you should check the oil the proper way. Drive the car and warm it up, shut the engine down and remove the dipstick and wipe if off, reinsert the dipstick and check the oil level. IF you have been adding a lot of oil lately, you may need to drain the oil, measure it and only add 6.5 quarts back in the sump, you can run the current oil though a paint filter. Then check the oil the proper way and keep an eye on the level over the next 4 tanks of fuel.

I have done basically that, and get the same readings I get cold, unless I check RIGHT after shutting off the engine, in which case it reads a bit low, because the oil has not all found its way back to the sump.

Regards,
Ray L.

 

What grade oil are you using?

 

5W30 Synthetic.

 

Try 5-40.