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Tracking my E46 Oil consumption issues

29K views 141 replies 31 participants last post by  Yewzer B Lewzer 
#1 ·
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?
 
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#4 · (Edited)
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.
 
#5 ·
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.
 
#6 ·
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!
 
#9 ·
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.
 
#12 ·
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.
 
#15 ·
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.
 
#18 ·
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.
 
#22 ·
Hello I am also a part of the mysterious oil losing club. Except this time I lost about a qt in 200 miles. Which is usually around 700-900 miles. I am thinking its the piston rings as their was an oil drip from the exhaust manifolds today after I shut the car down, and burning oil smell/and souund, and a lil smoke coming from that area. Also black soot in the exhaust pipe. Am I screwed, taking it to the mechanic tomorow to see what he thinks.
 
#25 ·
The oil drips on the exhaust manifold and burning oil smell are textbook VCG leak. Take care of the VCG and check the rest of the engine for leaks, specifically the OFHG and vanos line.

Of course theres no guarantee that leaks are your only issue. 1 qt/ 200 miles is really excessive. But for now take care of the leaks, make sure the engine is completely dry and monitor consumption.
 
#26 · (Edited)
I'd have to agree with Stinger: A lot depends on how the engine was broken in during the first thousand miles or so. I closely followed the manual after purchase (new) and at 130,000 miles I currently have zero oil consumption.

mikhit,

Great information on the BG product! It's nice to see someone impart information so well.
 
#32 · (Edited)
For what it's worth as a point of reference, my 02 325Ci runs OEM oil/filter changed around every 7500 miles. In that time period, I might burn through only half a quart of oil or less. The car has 108k miles.

I have replaced my oil filter housing gasket, which was leaking and causing oil dripping down the drivers side of the motor onto the oil pan. Also I replaced the Oil separator and all components, as the oil return line was seeping and brittle. But even when those were leaking, I never lost more then half a quart.
 
#38 · (Edited)
I really hope it makes a noticeable difference in the consumption rate. Fixing an internal oil consumption problem, like I mentioned before, is $$$. If this BG MOA product helps improve my consumption from one quart per ~700 miles to about ~1400-2000 miles, I'd be more than happy. That's almost normal spec for a M54.

I'm going to try this product, along with switching from OEM 5W-30 to a heavier 10W-40 and continue to record the progress.
 
#39 ·
I was having the same problem. I was burning roughly 1L/800KM - TERRIBLE...
Anyway, I started experimenting with oils. 0w10 european formulae. It didn't improve until I changed to the CASTROL 10W40 edge with spt. (http://images.oreillyauto.com/parts/img/large/cas/edge_blk_1qt-10w40_300.jpg)
The improvement took a little while and was slowly but it's still improving.
Initially it started out as
1L/1000KM. Topped off and it improved 1L/1200km. Topped off again 1L/1500km. NEXT I went for a long drive ~ roughly 400km drive. This time the oil lasted me about 1L/2500km. I thought great it's improving quite a bit but then it was highway drive. came back to city and light came on. I topped it off again it lasted roughly 1L/1500km. It kinda made sense that less was burnt in the highway and more in the city.
I just recently did an oil change. So far it's been 1500km. Fingers crossed. So far so good. Engine felt great today when I drove her so we'll see how long she lasts till she's thirsty again.
 
#42 ·
I offered a brief explanation of MOA in post #6. To recap: it is essentially ATF with other detergent additives.

The idea is that it will help clean and break up sludge or sticky components within the engine. People use MOA for a variety of reasons, including to help quiet noisy lifters (which may be sticking), as well as overall good engine health.

In the case of oil consumption, it is possible that MOA will help IF you're losing oil past the rings because they are sticking and not floating freely. Stinger's post #11 was a great overview of the purpose of each of the rings, and you can understand why they must slide freely.

But if your oil consumption is the result of some other internal issue, you probably will not experience much, if any, improvement.

So, I say again, this is certainly no cure all. I have personally experienced decent consumption improvement from my use of MOA over the last few months, and intend to continue to track it closely for more complete data. However, there is no guarantee that everybody's experience will be the same.

MOA from my dealership costs me about $12 a can (and evidently you can find it even cheaper online or buying in bulk), so its definitely worth a try IMO.

Good luck
 
#43 · (Edited)
Here is the direct quote for MOA

BG MOA® prevents oxidation and thickening of engine oil under even the most severe stop-and-go, high temperature driving conditions. It fortifies all qualities of engine oil to provide superior long-lasting engine protection and helps maintain optimum engine performance. BG MOA® keeps piston ring belts, hydraulic lifters and other engine components clean to help extend engine life and reduce costs of operation. It is compatible with both synthetic and petroleum-base oils. The Thin Film Oxidation Uptake Test (TFOUT), ASTM Test Method D4742, proves BG MOA

, proves BG MOA
 
#44 · (Edited)
, proves BG MOA***8217;s remarkable resistance to oxidation by more than 200% longer than six major brands of SL quality oil. At the conclusion of the API Sequence IIIF Engine Test***8218; a major brand, high-quality reference oil barely passed the 80-hour test with a viscosity increase of 255 percent. At 80 hours, another brand of oil fortified with BG MOA® had a viscosity increase of only 57 percent. At the conclusion of the triple-length, 240-hour test, it was still well within the viscosity limits with an increase of only 198 percent.
 
#52 ·
I too have been using BG products for years and most techs I know swear by it. The BG guys used to do a demo at a local Ford dealership. They have a Chevy 350 up on the bed of a truck. the 350 (obviously) runs MOA in the engine. They start the engine and let it warm up and then drop the oil pan and continue to run the engine for 45 minutes. They check bearing journals with an IR gun and the temps never go much over 400 degrees... Even after 45 minutes of running with no oil in the pan.

I bought a case a few changes ago. I too have had a mysterious increase in consumption recently. I just bought Mobil 1 0W-40 to try out. I'll need to change in the next 1k miles so we'll see.

BTW... BG stands for Bearing & Gear... They started as a bearing and gear company and looked for ways to improve lubrication. It looks like they found it with MOA. I need to get some 44K also... I'm out.
 
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