Tiny leak?

[deilenberger]

I believe I've mentioned before, my '07 seems to have a tiny oil leak. The boot on the front of the rear swingarm gets a slight mist of oil on it. Over 2,000 miles or so it isn't quite enough to form a drop.. but under the boot will have a smear of oil if I rub my finger over it. If I track the oil trail backwards (upwards actually), it seems to be coming off the top of the transmission, then running down the edge of the shift-switch/potentiometer onto the top of the boot. Again - barely a trail to follow, but something is there.

Whilst getting fuel-strip #4 today (the service adviser complimented me on bringing the bike in on the hottest day of the year in NJ.. was only 103F on the Parkway.. but I digress).. I asked the mechanic working on the bike to take a look and see what he thought. His thought was a rear engine seal. Which one he was uncertain of.

I think it's been like this for at least 5,000 miles or so, perhaps more (short term memory is the first thing to go..) and my engine oil level never drops, nor does my transmission oil level. If I wipe my finger and poke it toward my nose, it doesn't smell like the gates of hell (sulphur) so I don't think it's transmission oil.

I have an extended warranty (which includes seals, most don't) until next April. I'm planning a 1,500-2,000 mile trip in August to Canada and around NY state and New England... so I'm hesitant about (1) taking the bike in and have them tear it apart since I know things usually get backed up somehow, or some part isn't available, plus I'd like a few thousand miles on it before taking it on that long a trip; OR (2) leaving it like it is and figuring it won't get worse, and I'll have it attended to in the winter.

Anyone else have a very slightly moist front boot? Been that way for long? I know about the tendency for leaks to get worse, but so far this one hasn't. Clutch feels fine, so it's probably not the mainseal. I'm of a mind to fogeddaboutit until I get back from the trip, but need some brotherly/sisterly confirmation..

Was damn hot/humid in NJ, but riding is better then hiding in air-conditioning. So far I haven't melted, and compared to riding a K100RT in moderately warm weather, this ride was was a joy.

BTW - new fuel strip appears accurate so far (about 45 miles..) It got down to thinking I had 47 miles to go, filled up and the bike took 3.5 gallons. My MPG was someplace around 45 or so.. so it would have turned the light on at 40, leaving me about a gallon to find gas. Much better then my last strip that thought I had a 350 mile tank range (and then NO tank range.) Maybe this one will last for a while.

[winkeldc]

I've noticed the same thing on my 08. I can see a slight build up on the front of the boot, but didn't take the time to fully investigate the source. I had to store my bike for a year for a trip abroad while my wife does a teaching exchange in Australia. What's under the boot? Is there an u-joint or other coupling under there that could fling the oil off? I have ridden the past 10k since I first noticed the problem and the dealer's response thus far has been to watch it to see how much comes off. My dealer, at least, seemed unconcerned. Maybe they were waiting for my warranty to expire. Sorry I couldn't be more help.

Dave

[deilenberger]

While there is a U joint under the boot (and the transmission output shaft seal) - leaks from inside shouldn't be able to get on the outside, especially the top. The boot seals at both ends. At the transmission end it's held on with a tie-wrap, at the swingarm end, it expands inside the swingarm and should make a decent seal. What I'm seeing appears to be coming from up higher..

[MTBeemer]

No insights on what is causing the oil flow, but were it happening to me, I would ride the bike with confidence until the winter. It is very unlikely that the source of the leak will grow to the point where it makes the bike difficult or impossible to ride in the next 5-10K miles.

[hjsbmw]

I had an oil leak fixed under warranty 2 years ago. I did not have any build up around the front boot. I did have oil forming on the gear potentiometer, but it was unmistakably transmission oil (foul smell) coming right out of the potentiometer. They told me that I did have an engine oil leak in addition, and that came from the counter balancer shaft seal. That may be a candidate in your case. The repair took 5 days, and it did involve overnight ordering of additional parts because they found more leaky seals (front and rear main).

I rode with the leak for a few hundred miles only, but I am convinced I bought the bike like this from the first owner. Despite of that, my clutch never started to slip. I believe that usually it's gear oil (not your case) that gets on the clutch. What could you live with more easily, ride with the risk of progressive seal failure of an already failing seal or having a fixed bike where you don't know if it was fixed right? Ultimately, it may also be a matter of how soon your dealer can even get to it.

[websterize]

I'm struggling to envision where on the bike this is occurring. Could someone advise on which parts fiche illustration shows it or post a photo? Nylife and I had a mysterious seepage on our bikes, and I wonder if it's the same you're describing, Don. While under warranty, I mentioned the seepage to the service tech, and he dismissed it as engine-oil overfill, which didn't ring true, but I didn't press him for a better explanation.

[Oaktown]

Don,

As we know, BMW's don't leak anywhere unless something is not right. I've been down this road previously, with a small leak exactly where and how you describe yours, which progressed into replacing 5 different seals and $1,500. at 30 months old and 39K miles (BMW declined to assist with the repair cost). My 2007 was built in September of '06 and I was told the seals were "re-designed" from 10/06 forward. IMO, I would not bet that a leaking seal will never get worse; on the contrary, you are being warned that failure is only a matter of time. 2K, 5K, 15K miles or ...? Who knows, but that seal(s) is gonna fail at some point. You've got coverage, so what is the benefit of waiting for a time not of your choosing? Of course, just my two cents.

John

[websterize]

Here's nylife's photo from the "Should I be concerned" topic:

[deilenberger]

Since Bill asked:

Some pics. First one is without flash, and it shows what it really looks like. The rest are with flash and they make it look worse then what it is (the oil reflects the flash..)


NO FLASH


Same WITH flash.


With flash.


With flash.

As far as the suggestion of overfill, well, yes, last oil change I was a bit above the top of the window (after overnight on the centerstand.) It's now down about 1/8" below the top of the window, so it might be interesting to clean it up again and see how it looks after some riding.

John, I do intend to get it fixed, but when is the question. It has been this way for quite a while.. and it hasn't gotten any worse that I can see. My bike has a 10/06 production date, which I'd hoped got it out of the balance shaft seal issue. It sounds as if your dealer shotgunned the seals, replacing everything in the area while they had it apart. That's not necessarily a bad thing since the big expense is the labor on the job. It's a safe choice on the part of the dealer since they'd probably have to eat the labor if a 2nd seal started leaking later on.

My question was - if anyone else has seen this sort of misting, and if so - how long did they have it for (and did it ever really progress to a real leak)? As I mentioned, leaving on a 2k mile trip out of the country on a freshly repaired bike isn't my scenerio of choice.. and if the insurance company waffles on covering it (I'm sure they will, that's how they play) and the dealer is backed up (probably is - took over a week to get an appointment for a fuel strip replacement) - it could easily come down to the repair bumping into the trip date. Conversely if someone had it progress from misting to spurting oil with no warning, then it would be wise to do it before the trip.

BTW - John, I can tell you haven't owned an airhead. "Misting" is considered pretty much normal behavior on any airhead engine over a few years old.. from around the rubber pushrod tubes. BMW even made a special tool to bang the pushrods into the engine case more to slow down the misting. At least they're not like my old brit bikes where..

Of course I could eliminate all the fuss and just buy the nice red one in the showroom.. but that means moving all the farkles over and getting this past SWMBO somehow..

[Oaktown]

Don,

You're right, I never had an airhead. When I first noticed the misting, I thought nothing of it since when I rode a Triumph in the 70's, I had to keep a good supply of oil(s) handy and that's why I missed my opportunity to get the repair done under warranty. When I relayed the above to the dealer hoping for an accommodation on the repair once it became obvious I had a problem, that's when I was informed that "BMWs don't leak". The concern for a proper repair is not unfounded; BMW will warranty repairs for 2 years and yes, the job had to be re-done. I'm past the 2 years now @ 54K miles and my fingers are crossed. Enjoy your trip.

John

[deilenberger]

After taking the photos, I wheeled the bike out of the garage and cleaned the area where the oil is really well this time. Used carb cleaner and then MAF cleaner to remove the residue from the carb cleaner (CRC-MAF cleaner evaporates almost instantly, leaving no residue.) I then used my protoscope (actually a boroscope meant for automotive use, but it looks a LOT like what was used for my last colonoscopy) and poked around trying to find the source. Damned if I can find it.

I was able to get the boroscope into areas like ahead of the airbox - between the front wall of the airbox and the engine - nothing, dry as a bone. Looked around the entire joint of the transmission to the rear of the engine, nothing. Got partly under the airbox with it, nothing. Spent about an hour looking and found no smoking guns (or oil accumulation.) It's a mystery to me.. I think the boot is tight, but I can wiggle it a bit where the tie-wrap holds it on the rear of the transmission flange. I'm going to look for a long thin tie-wrap and remove the one that's on there and see if there is any sign of leakage inside the swingarm at that end (there is none at the other end.) That will also let me check the bottom folds of the boot for any damage.

I'm also thinking of R&R of the starter, and see if there is any sign of oil inside the clutch housing. If there is any in there, it should be quite visible with the starter removed and my boroscope poked up in there.. Starter is easy to remove, and it will give me a chance to grease the bendix on it, which is worth doing anyway.

John - the 2nd time yours started leaking, was it misting again or gushing? Do you have the service order for the warranty repair? I'd be curious what seals are listed on it (PN's are fine).. since I doubt if they'd replace all 5 of them a second time, they might just have replaced the one that started leaking again.

Going for a ride tomorrow to see if I can produce any signs of leaking..

[deilenberger]

Found something significant..

I removed the side panels on the starboard side (right, sitting on the bike), and removed the air snorkel and air filter.

OIL! In the airbox. There were little puddles of it about 1/8"-1/4" deep in some of the valleys in the bottom of the airbox. It's not easy to get a hand in there since the snorkels to the throttle-bodies take up a lot of the inside, but I managed to soak most of it up with paper towels, followed by rags on a grabbie-stickie thing I have in the special tool drawer (meant for picking up dropped nuts.) I used the boroscope to see what the inside looked like and found the puddles. Also tried taking photos, but since space is tight, I doubt if they'll be good for much. No idea how the oil got out to mist down on the boot, but since there was oil where there shouldn't be any, I'm guessing this was the source.

With the side-panels off I was also able to scope out more of the engine, and no signs of any leaking at all. That's a good thing.

Guess I have to watch how much oil I dump in when I change the oil (appears that 4 quarts may be a bit too much.)

Next - a ride to see what I see.

Bill, thanks for the reminder of the thread on oil weeping out of the airbox.. it was the impetus to open it up and look.

BTW - I'm justified in my fear of someone else working on the bike. When I removed the side-panels, the two screws holding the throttle-body cover on weren't BMW issue screws. No integral washer on them. They were when it went in.. Luckily, I'd bought extras of these screws, so they're the correct ones now. This panel had to be removed to put the new fuel strip in, not to point fingers, but unless someone snuck into my garage and swapped screws I have a guess as to how they got there. I guess I should be thankful there were screws there.

Happy Monday!

[websterize]

Thanks for the update, ambassador.

Oil weeping from the air box seam has reappeared on my bike. I, too, wonder if the cause is oil in the air box.

Lost Rider detailed removing the side panel, snorkel and air filter in his 24K-mile maintenance post. I take it you took the same steps to get inside the air box?

At the recommendation of a dealer service rep., and based on the theory I was overfilling at top-ups, I switched from keeping the oil level to within a whisper of the top of the circle to keeping the maximum level at the center dot. Hopefully, this change, and cleaning out any residual oil gunk in the air box, will keep me from weeping down the road. Incidentally, I switched to OEM synthetic at the 6,000-mile service.

[Catchina]

I have never filled it more than a tiny bit past 1/2 of the round window, is filling it to near the top of the window too much?

[Bob Ain't Stoppin']

Found something significant..
OIL! In the airbox. There were little puddles of it about 1/8"-1/4" deep in some of the valleys in the bottom of the airbox.

Don, Not to tell you what to do, but you're policy of filing the oil to the top of the sight glass is wrong. The center dot is the full mark. These boxer engines have enough trouble with keeping the oil inside the casing without adding to the problem by over filling. I'm sure you are aware of the evolving design of the air separator used in the crankcase vent system. The current one works pretty well, but can't completely cope with a high oil level. Hence you're leakage.

[deilenberger]

Found something significant..
OIL! In the airbox. There were little puddles of it about 1/8"-1/4" deep in some of the valleys in the bottom of the airbox.

Don, Not to tell you what to do, but you're policy of filing the oil to the top of the sight glass is wrong. The center dot is the full mark. These boxer engines have enough trouble with keeping the oil inside the casing without adding to the problem by over filling. I'm sure you are aware of the evolving design of the air separator used in the crankcase vent system. The current one works pretty well, but can't completely cope with a high oil level. Hence you're leakage.

Bob,

Well, it went for at least 50,000 miles before this happened, and I've always filled it to the top of the window when changing the oil (as the manual specifies I believe..) I'm talking a bit with some mechanics who I trust about it, and will see what their recommendations are. Given the level of the oil window in the sump, and the small amount of oil that takes it from middle of the window to the top of the window, I think it really takes a larger overfill (like my 4 quarts instead of 3.8 quarts, which is about what I usually put in..) and the last oil change I remember I really debated about pouring the last 2/10ths of a quart in. Guess I should just go on quantity when doing the change. Whatever, I believe I did overfill it, and that explains the leak. The current oil seperator (the fan on the end of the camshaft) seemed a clever design, but as you said - with a gross overfill, something is going to get past it. I've proven that apparently.. I've seen the center-dot being described as the "full" mark, but I've never seen that in anything in writing from BMW. I have seen the top of the window described as full in BMW literature (it may well be in the owners manual, I'll have to look..)

Anyway - no harm done at least, and no need to split the bike in two.

Bill - yes - if you can find a DIY for changing the air filter, you'll have access to the airbox. Briefly what it involves is:

2 x T10 screws that hold the throttle body cover on (one at the front, one underneath toward the rear), then wiggle it down out of the side panel (it has a rubber stud that goes up into the sidepanel.)

5 x T10 screws hold the side panel on. One at the front, then two al g the top after you remove the seat, then one underneath (you have to get down on your knees to see this one.) The panel just lifts off.

At this point you can see the entire snorkel. At the top and bottom where it slides into the bracket on the airbox, there are locks to hold it in position. The release on them is toward the center of the bike. Press the release down, then wiggle the lock out a bit. Once both are out, you can wiggle the snorkel out of the bracket. It also has a stud that holds it into a rubber lined bracket on the frame about midway on the back of the snorkel. It will pull right out if it.

Once the snorkel is off - you can remove the filter. It was easiest to get it started at the top, and then work it out all the way around. It's about 2" deep, so you have to get the whole thing out to have access.

Then if you have small hands, you can get your finger down in the airbox and feel around for oil. Undoutably you'll have some. The bottom of the airbox has valleys in it that the oil collects in. Best bet is a long set of forceps with some folded paper towel clamped into it. Push it down into the valley and oil, and just let it soak it up. I finished it up with some scraps of towel held in a funky tool I have ( short handle, long shaft, thin, clamps stuff at the end of the shaft.) I think I got most of it out.

On the R1150 series bikes there was a purposely built in low spot in the airbox, with a drain screw that you could open to drain out the oil. It used a slightly different crankcase breather then the current setup has. The current breather hose looks like it should drain back into the engine, and it probably will drain some oil back if the bike is on the sidestand, but the valleys in the bottom of the airbox aren't going to drain back.

Simple enough job, and as long as you don't drop something hard into the airbox, you'll be fine with DIY. There is probably an air-filter change writeup on the BMW-MOA hexhead DIY subforum, complete with pics. If not - I might do one there.

PS: Just looked at Joe's DIY, it's good and gives you an idea of what to remove to get to it.. he didn't describe all the screws, so what I wrote above may be of some use to you along with Joe's writeup.

[hjsbmw]

I have seen the top of the window described as full in BMW literature (it may well be in the owners manual, I'll have to look..)

The owners manual clearly describes the top as max, not the center, but they are also very clear on that you have to check with the engine hot. Oil expands with heat. It's easier to add oil than to drain it when you realize it's overfilled.

[deilenberger]

125 mile report.. bone dry. So far, so good. If it starts up again it's back into the airbox I go.. (still haven't figured out how it gets out of the airbox to mist up that area, but.. evidence so far says that's the cause. There is one fitting inside the airbox in the bottom on the port side that I saw with my boroscope. No idea what it is, appears to be a brass fitting in a molded in recess in the bottom. Maybe an automatic drain valve in case you suck up a bunch of water?)

[deilenberger]

Update report - about 350 miles on it now. Still dry dry dry! Wheeeee!

[websterize]

There was oil in my air box, too. Tried cleaning, but large hands do make it difficult. I used foam paint brushes to wipe it out. No pools that I could see. More droplet-sized. Not really alarming amounts. It's difficult to see inside the air box let alone take photos.



Don, I think I know how the oil got on your boot. In the photo above, you see the oil seepage that has reappeared along the seam. Below it, there is also oil smear on the bottom edge of the air box. Although you can't see it, there is a budding droplet of oil on the under corner of the air box behind the frame. See how that corner looks wet in the photo? That corner is directly above the fore rubber boot. Oil weeps out of the seam, flows aft along the edge to the corner. Drip, drip. Now, I only have ~14K on the odometer. Were I to have a gazillion, as you do -- and with our similar fill-it-to-the-brim engine oil topping up -- I'd probably have as much yuck on my boot. So, I suspect, it's not oil misting but oil dripping. I'm gonna keep the oil level no higher than center dot on the glass and hope that fixes it.

Had a bit of a scare during surgery. I'm off work Fridays, so Nurse 2-year-old was "helping out," handing me tools, singing, etc. Like me, she finds the bike endlessly fascinating. I was inspecting the air box innards with a small Surefire flash light when she, all of a sudden, said "my turn," and proceeded to drop the flash light inside the air box. I let out a Homer-Simpson-like shriek, which brought some tears for both of us -- more her than me. I fished it out, we're getting ice cream later today.