Tracking my E46 Oil consumption issues

Alright,

I've been having oil consumption issues with my 02 325Ci for a quite a while now, almost 2 years. Do to school, I had not the time, nor funds to properly diagnose the issue. I just want to throw my status up on here and see if anyone else has an idea on what can be causing the issue.

Backstory:

My car has 135K miles on the M54. I run BMW 5W-30 and I check the oil manually and have to add a quart of oil every +/- 700 miles (2 weeks). I daily drive my car, nothing too far, no traffic at all. I do not drive the car hard at all, It will go months without going over 4500RPMs.

At first, because of the rate of consumption I was sure I had an external leak of some sort. I looked in all the normal prone areas, didn't see anything visible. However, I replaced many parts anyways do to preventative maintenance in hopes one of the parts might be the cause of the oil problem.

I replaced the VCG and grommets, I also replaced the Vanos seals with the Besian kit... The consumption continued. Then I replaced the Oil filter housing gasket and the full Crank Case Ventilation system and dip stick seal, hoping this will be the cause... Much to my disappointment, the problem persisted.

I then took the car into my mechanic, explained the issue and showed him the chart of consumption I had been keeping for months. We pulled the car on the rack, removed all the under panels and both visually checked the undercarriage for any sign of oil leaks. Nothing. The engine bay is clean of oil. He then suggest the problem is internal, I'd never seen any black smoke coming from the exhaust ever. However, he suggests my next step will be a compression/leak down test to confirm.

I am reluctant to have the test done because even if it is confirmed to be internal, it just means a very costly repair. At that point it would just be more feasible to sell the car or trade it in and let a dealership eat the cost. I just wanted to see if any of you guys have an opinion or a suggestion on what the problem might be or if I might be overlooking something...? What do you guys think?

Outside the U.S the dealer oil would be an LL01 spec XW40. Give that a try

Originally Posted by sprintman

Outside the U.S the dealer oil would be an LL01 spec XW40. Give that a try

I did try using a LL01 Castrol 10w-40 for a while. The thicker oil seemed to slow down the consumption slightly. However, it was no solution.

You are doing everything correctly. Very unusual!
Likely valve stem seals or oil rings (btw, these will not show up on compression test--what is your mechanic thinking?).
How does the inside of your tailpipe look?
Might be best to keep adding oil and run with it.

someone beat this car when it was new, or was neglectful on oil changes badly.

Originally Posted by Stinger9

You are doing everything correctly. Very unusual!
Likely valve stem seals or oil rings (btw, these will not show up on compression test--what is your mechanic thinking?).
How does the inside of your tailpipe look?
Might be best to keep adding oil and run with it.

someone beat this car when it was new, or was neglectful on oil changes badly.

I've owned the car since 2007, bought with 60k. I've always maintained the car very well. The inside of the exhaust tips are black from soot. Is that not normal? The leak down test will conclude whether or not a cylinder has too much seepage pass the rings. Adding oil and keep on going is what I've been doing since the problem began, however, I want to possibly isolate the problem.

I have been in the same boat as you for a little over a year now with my 03 325. I started experiencing increasing oil consumption, followed the same procedure as you replacing the various gaskets, ccv, etc...all the usual suspects. All the while documenting the consumption and not seeing any improvement. I, too, noticed blacker than normal exhaust tips...

Stinger is correct, the compression test will likely not help identify the internal source of the consumption. I had a conversation with the shop foreman at my local dealership, with whom I have a very good rapport. First, he explained that a compression test would not likely be beneficial and just be a waste of the money. He also explained that the valve stem seals are an uncommon source of consumption on this engine. He was pretty confident that it is the rings, and went on the say that they are most likely sticking and not allowed to float properly.

Anyway, his suggestion was to use a can of BG MOA every ~3000mi as consumption persists at is current rate. He explained that the MOA was essentially just a little ATF with some other detergent additives and "could" help free up the sticking rings (he also cited personal success with the product). Well, I have been running MOA in my oil for about 3 months now and have seen improvement. My consumption went from 1 qt every ~600-700 miles, to my current rate at 1qt/~1100miles, and it continues to improve. I have been pleased with the results so far, albeit rather preliminary. If I can get to 1qt/1500-2000mi I will be very happy.

I've seen very little mention of MOA on these or any other BMW forums. BMW approves the use of the additive and it is sold at my local dealerships. Once I have full data, I plan to create a thread documenting my results.

In the meantime, might be worth a try...good luck!

Good info

Originally Posted by mikhit

I have been in the same boat as you for a little over a year now with my 03 325. I started experiencing increasing oil consumption, followed the same procedure as you replacing the various gaskets, ccv, etc...all the usual suspects. All the while documenting the consumption and not seeing any improvement. I, too, noticed blacker than normal exhaust tips...

Stinger is correct, the compression test will likely not help identify the internal source of the consumption. I had a conversation with the shop foreman at my local dealership, with whom I have a very good rapport. First, he explained that a compression test would not likely be beneficial and just be a waste of the money. He also explained that the valve stem seals are an uncommon source of consumption on this engine. He was pretty confident that it is the rings, and went on the say that they are most likely sticking and not allowed to float properly.

Anyway, his suggestion was to use a can of BG MOA every ~3000mi as consumption persists at is current rate. He explained that the MOA was essentially just a little ATF with some other detergent additives and "could" help free up the sticking rings (he also cited personal success with the product). Well, I have been running MOA in my oil for about 3 months now and have seen improvement. My consumption went from 1 qt every ~600-700 miles, to my current rate at 1qt/~1100miles, and it continues to improve. I have been pleased with the results so far, albeit rather preliminary. If I can get to 1qt/1500-2000mi I will be very happy.

I've seen very little mention of MOA on these or any other BMW forums. BMW approves the use of the additive and it is sold at my local dealerships. Once I have full data, I plan to create a thread documenting my results.

In the meantime, might be worth a try...good luck!

I am a big fan of BG MOA and have been using it for the last 10yrs on my 323. I have about 10 cans of MOA and 20 cans of BG 44K on my shelf

sent from my HTC EVO+ using Bimmer App

I too am in this boat my bimmer is using oil at the same exact rate every +/- 700 miles I'm adding a quart of oil. I religiously change my oil every 7,500 miles, this problem didn't exist with my M52TUB25 block. My old block never lost an ounce of oil in over 330,000 miles. At 330,000 after a spun bearing I upgraded the block to an M54B30 block, crank shaft and injectors and a new oil consumption issue. I've done the leak down test, compression tests as well as vacuum leak test and they all came back negative. I've changed the VCG and oil housing filter. I beginning to believe the M54 motor just burns oil more oil than any other BMW motor; I just don't know why... I'm currently just over 338,700 miles. I currently keep at least three quarts of Mobil 1 0W-40 in my car at all times.

Great post Z

323i and 328i FTW!

Originally Posted by mikhit

I have been in the same boat as you for a little over a year now with my 03 325.
In the meantime, might be worth a try...good luck!

I agree with all wrtten in this solid post.

And just for clarification, there are two kinds of rings: compression rings and oil rings. A compression test will test the two compression rings, but not tell you anything about oil rings. The test for the latter is more esoteric, as I found when I researched this myself online. If you want to do this and cannot find the info, let me know.

Start here: http://wiki.answers.com/Q/How_do_you...d_piston_rings


And for those who want to learn more, the net always has those who are more erudite:

No matter how much we love them, our engines are still basically inefficient air pumps and need all the help they can get to make power. Like any other type of pump, if it leaks, it won't work. And since it's the pistons that are doin' the pumpin', if they're allowed to flop around in the bores, they'll leak and little power would be the result. Not only would power suck, the pistons, along with the rest of the engine would quickly destroy itself.

Your rings may look like ordinary bands of steel, but they are far from simple in their design and construction. They work to locate the pistons in the bores while sealing the cylinders for power and directing oil to the proper spots to keep the engine alive. Ring thickness, tension, shape, material, and profile all play a crucial role in cylinder sealing, power making, and oil control.

The Fire Ring
The top ring's main job is sealing the combustion process and many refer to it as the "fire" ring. The top ring works in a dual capacity by holding high vacuum as the piston moves down its bore and by keeping cylinder pressures high when the combustion process begins. Ring gap is critical and, if left uncontrolled, much of the combustion gasses would simply escape into the crankcase. Anytime you allow cylinder pressure past the rings, (otherwise known as "blow by"), you are losing horsepower.
Small Block Rings Cutaway Ring
This cut-away clearly shows the gapless top ring's twin overlapping ring design.

Utilizing a two-piece, overlapping ring design with their gaps placed 180 degrees apart; gapless rings are engineered to eliminate as much blow by as possible. Obviously, a small amount of combustion gasses will always leak past the top ring, but that is helpful in creating the proper seal for the second ring. Performance top rings will usually be marked to identify which side faces up in the bore. That's because the inner diameter of the top ring is tapered to force the rings out and increase the seal against the cylinder walls as the piston goes up the bore. If installed upside-down, the top ring will lose power.

The Second Ring
The second ring serves as a back up to the top ring in sealing the crankcase from the combustion process. But, more importantly, it acts as an oil scraper to keep any oil that has migrated past the oil control rings from seeping into the combustion chamber. The second ring usually features a smaller gap than the top ring, due to the lower amount of heat and correspondingly less expansion it will see. In almost every case, cast iron is the material of choice for the second ring and it will typically not have a face coating.

The fact that the top ring absorbs the majority of combustion abuse allows a cast iron ring to be used in the second groove of almost any engine. Second rings are designed several ways; with the reverse-torsional taper face being the most common. The taper face allows the ring to ride over the film of oil on the upstroke and scrape oil off the cylinder walls on its way down. The other basic second ring design is the wiper ring that has a groove cut on its bottom face to wipe oil down.
Small Block Rings Hand Powered Ring Grinder
The most affordable compromise between cost and efficiency when filing rings is still a ha

The Oil Ring
The last ring set is just as important as the rest, yet often ignored. The oil rings are critical to maintaining engine life, as well as controlling detonation. Oil rings are very thin chrome-faced stainless steel bands with stainless steel expanders in between. Oil rings do not need to be gapped, but their fit should be checked prior to installation to make sure the ends don't butt together. Both standard and low-tension oil rings are available. However, low-tension oil rings should only be used in engines equipped with an external vacuum pump. Otherwise, excess oil may seep into the combustion chambers where it could ignite and cause detonation.

Read more: http://www.superchevy.com/technical/...#ixzz2FEy1eio5

Originally Posted by Zchild

I too am in this boat my bimmer is using oil at the same exact rate every +/- 700 miles I'm adding a quart of oil. I religiously change my oil every 7,500 miles, this problem didn't exist with my M52TUB25 block. My old block never lost an ounce of oil in over 330,000 miles. At 330,000 after a spun bearing I upgraded the block to an M54B30 block, crank shaft and injectors and a new oil consumption issue. I've done the leak down test, compression tests as well as vacuum leak test and they all came back negative. I've changed the VCG and oil housing filter. I beginning to believe the M54 motor just burns oil more oil than any other BMW motor; I just don't know why... I'm currently just over 338,700 miles. I currently keep at least three quarts of Mobil 1 0W-40 in my car at all times.

More power to you for investing in a new engine in a chassis with 330K on the odometer!
I assume you meant you replaced the oil filter housing gasket?

And not true about the M54 engine. I bought my car new and broke it in like an old man. Change oil every 7500 and last typical change at 9000 miles showed the oil level down only a few ounces without any oil added between changes.

Originally Posted by Stinger9

More power to you for investing in a new engine in a chassis with 330K on the odometer!
I assume you meant you replaced the oil filter housing gasket?

And not true about the M54 engine. I bought my car new and broke it in like an old man. Change oil every 7500 and last typical change at 9000 miles showed the oil level down only a few ounces without any oil added between changes.

Thanks, good to hear that there is an M54 motor somewhere that's not an oil hog. I can begin anew on tracking down the cause of this oil issue because there are no leaks and there's no oil on the ground. It has to be going somewhere unless the motor is burning it up at a much higher rate for some reason...

How do you use the BG MOA?

Just pour into the engine via the oil cap?

Originally Posted by nike001

How do you use the BG MOA?

Just pour into the engine via the oil cap?

Yes. IIRC, the instructions on the can recommend using 1 can (~.3 liters) per 4-5 quarts of oil. When I was about a quart low I just added 1 can and topped up with oil. I repeated this again about 3000 miles later (after having consumed 3 or 4 more quarts).

It probably goes without saying that if you're not burning significant amounts of oil you should only add MOA during an oil change. You don't want the ratio of MOA to oil to exceed the 1 can per 4-5 qt recommendation.

Also, great info on the two kinds of rings and the differences between them in post #11.

Thanks Stinger!

Originally Posted by mikhit

I have been in the same boat as you for a little over a year now with my 03 325. I started experiencing increasing oil consumption, followed the same procedure as you replacing the various gaskets, ccv, etc...all the usual suspects. All the while documenting the consumption and not seeing any improvement. I, too, noticed blacker than normal exhaust tips...

Stinger is correct, the compression test will likely not help identify the internal source of the consumption. I had a conversation with the shop foreman at my local dealership, with whom I have a very good rapport. First, he explained that a compression test would not likely be beneficial and just be a waste of the money. He also explained that the valve stem seals are an uncommon source of consumption on this engine. He was pretty confident that it is the rings, and went on the say that they are most likely sticking and not allowed to float properly.

Anyway, his suggestion was to use a can of BG MOA every ~3000mi as consumption persists at is current rate. He explained that the MOA was essentially just a little ATF with some other detergent additives and "could" help free up the sticking rings (he also cited personal success with the product). Well, I have been running MOA in my oil for about 3 months now and have seen improvement. My consumption went from 1 qt every ~600-700 miles, to my current rate at 1qt/~1100miles, and it continues to improve. I have been pleased with the results so far, albeit rather preliminary. If I can get to 1qt/1500-2000mi I will be very happy.

I've seen very little mention of MOA on these or any other BMW forums. BMW approves the use of the additive and it is sold at my local dealerships. Once I have full data, I plan to create a thread documenting my results.

In the meantime, might be worth a try...good luck!

Thanks for the suggestion.

I've heard of BG products before. I've never really looked into their MOA line. You mentioned the slight improvement in consumption and I must ask if your driving conditions have changed at all in that time frame? Things like high RPMs and traffic seem to cause a faster rate of consumption for obvious reasons.

I'm going to ask my mechanic about the MOA, I know he's an advocate of their 44k product. I'll see if he can get me a couple cans and I'll run it. You add one can every 3000 miles?

Also, had you have had a cylinder leak down test? This could possibly isolate the source of blow by to a specific piston or oval cylinder. I sort of want to have to test done so I can confirm its the pistons and eliminate valve steam seals as a potential cause.

Cylinder leak down test only tests the compression rings. Oil rings are a completely different story.
I too am using some oil. 1 qt~800 mi. I have MOA at my shop and I am going to give it a try.
Normally bad valve stem seals will give you a puff of blue smoke at start up. I don't have this.
I am suspecting oil rings.

Originally Posted by zuckuss00

Thanks for the suggestion.

I've heard of BG products before. I've never really looked into their MOA line. You mentioned the slight improvement in consumption and I must ask if your driving conditions have changed at all in that time frame? Things like high RPMs and traffic seem to cause a faster rate of consumption for obvious reasons.

I'm going to ask my mechanic about the MOA, I know he's an advocate of their 44k product. I'll see if he can get me a couple cans and I'll run it. You add one can every 3000 miles?

Also, had you have had a cylinder leak down test? This could possibly isolate the source of blow by to a specific piston or oval cylinder. I sort of want to have to test done so I can confirm its the pistons and eliminate valve steam seals as a potential cause.

Your question about my driving habits is a really good one, because as you noted that will affect consumption. But no I haven't altered my driving at all. I do believe that the improvement in consumption that I am experiencing is a result of the MOA. However, as I alluded to before, I am working off of limited data at this time, and won't make any absolute conclusions until I have more complete data.

So far I have added the MOA at a 3000 mile interval. This interval works out to maintain a reasonable concentration of MOA with respect to the rate at which I am consuming oil, without exceeding BG's recommendation of MOA to oil ratio. Looking ahead, I will most likely just add a can during my regular oil change and then 1 more between my 7500 mile oil change interval...however this should all be adjusted for individual rate of consumption...

I never did get a compression test; deemed it would be inconclusive and thus not worth the expense...

Originally Posted by mikhit

I never did get a compression test; deemed it would be inconclusive and thus not worth the expense...

You can do a compression test yourself with a cheap gauge. Simple; I did it when I was 17 yo. Easy DIY.