Overfilled engine oil

[woodscrew]

Apparently I overfilled my 99RT before I went for a ride today (360 miles).I noticed some oil spray on the front of the left side case and followed it forward to the left cylinder. Some small amount had collected in the cooling fins and all of it seems to be coming from around the filler plug.At first I thought it might just be time for a new o-ring and plug.However, when I checked the sight glass at the end of the ride it was all oil.Usually my bike will lose a small but discernible amount on a long ride.Not so this time, so I guess I overfilled it some. Would that cause oil to weep out the filler plug? Or create any other problems? Bike ran great all day. I'll drain some out and refill properly. Thanks

[Firefight911]

This could be caused by the lack of air space in the crank. I would definitely check your airbox for oil. It is a common place to find oil in and overfilled crank case. There is a drain at the bottom of the airbox that you can let the oil accumulation out from.

 

Double check the o-ring integrity on your filler plug and make sure it is nice and clean.

[Ken H.]

It would have to be a lot overfull to be blowing out the filler.

 

While it sounds like the bike is indeed overfilled, I suspect your leak around the filler is still related to the O-rings (remember, there are two).

[Jerry Johnston]

Remember it will look overfilled until the engine has had a chance to cool down some. Also make sure the bike is sitting level.

[woodscrew]

Ken H. Two o-rings? I just looked this morning and I see only one on my plug.None hiding in, on, or around the plastic insert in the actual hole in the valve cover. Also looked hard for other potential sources for the leak (gaskets etc.) and see none.I leaned the bike slightly past level to the right and can see oil/air line in the sight glass so I guess I didn't really overfill it by much.

Thanks Dave

[Bud]

It would have to be a lot overfull to be blowing out the filler.

 

While it sounds like the bike is indeed overfilled, I suspect your leak around the filler is still related to the O-rings (remember, there are two).

 

I don't have two either.

[Blue Beemer Dude]

It would have to be a lot overfull to be blowing out the filler.

 

While it sounds like the bike is indeed overfilled, I suspect your leak around the filler is still related to the O-rings (remember, there are two).

 

I don't have two either.

 

Ditto. One.

[Jerry Johnston]

One on the plug and one on the seat (part you screw the plug into). Either one can leak.

[Bud]

One on the plug and one on the seat (part you screw the plug into). Either one can leak.

 

Didn't even know there was another part (the seat).

[lgoldy46]

two http://realoem.com/bmw/showparts.do?model=0418&mospid=48862&btnr=11_1704&hg=11&fg=20

 

[Ken H.]

two http://realoem.com/bmw/showparts.do?model=0418&mospid=48862&btnr=11_1704&hg=11&fg=20

Yes, and number 6 in the diagram, the inside one, is the more common leaker of the two.

[woodscrew]

Ken H. - I bow down to superior knowledge. Thank you.... now, do you know how to remove the seat? By the way, I checked the airbox and found no accumulation of oil.

Dave

[Ken H.]

Well there's been a couple of different ones. Some are just a press in. The best way I think to remove them is take off the valve cover and tap it out with a small drift from the inside. A piece of wood dowel or something will work.

 

Some of them are held in with a small Allen screw that you loosen. Again the best way is from the inside. Then they just pull out. If on those you can get the Allen screw loose from the outside (without dropping your Allen wrench in!) a good tug with your finger and it will (usually) pop out.

[Davis]

If it's the stock black plastic plug in a black plastic seat, there is no set screw. Some of the aftermarket aluminum seats have a set screw. You can pull the valve cover if you like, but the seat is just a light press fit. You can carefully pry up on it with a large screwdriver to pop it out. After replacing the o-ring, note there is a tab which fits into a slot in the valve cover when you go to press it back in.

[woodscrew]

Davis

I just finished installing the new oil fill seat.Thanks for the tip on removing the old one - popped right out with a screwdriver.My dealer told me to spray the new one with silicone for ease of installation, which I did. I'll let everyone know if it pops out while running due to the lube. It did go in easy. Thanks all.

Dave

[sonofdennis]

I often feel like I'm chasing oil levels from oil change to oil change. Is there a thermostatic valve to the oil cooler that can cause some oil to remain in the cooler during an oil change? Reason I ask is some times I get a nice oil level in the site glass even after the bike appears warmed up. Then I go on a longer ride and get it what I would call completely heat soaked. After that all I see is oil in the site window, no air/oil line of departure.

 

Alan

[ncsonderman]

Davis

I just finished installing the new oil fill seat.Thanks for the tip on removing the old one - popped right out with a screwdriver.My dealer told me to spray the new one with silicone for ease of installation, which I did. I'll let everyone know if it pops out while running due to the lube. It did go in easy. Thanks all.

Dave

 

Pretty easy once you know it's there Cheepest fix of any problem thusfar!

[Ken H.]

I often feel like I'm chasing oil levels from oil change to oil change.

Quit chasing it. It doesn't make that much difference. Put the proper amount of oil in it at a change, by measured volume, not by the sight glass. Then watch the sight glass over time. if it repeatedly trends downward, to where you repeatedly see the level between the very bottom of the sight glass to the 1/2 way point, under the same repeated conditions (did I mention "repeatedly"?), then and only then, add a couple of ounces.

 

The boxer holds almost a gallon of oil and from bottom of the glass to the top only represents a change of a few ounces. It just isn't going to make any difference.

[SWB]

I often feel like I'm chasing oil levels from oil change to oil change. Is there a thermostatic valve to the oil cooler that can cause some oil to remain in the cooler during an oil change? Reason I ask is some times I get a nice oil level in the site glass even after the bike appears warmed up. Then I go on a longer ride and get it what I would call completely heat soaked. After that all I see is oil in the site window, no air/oil line of departure.

 

Alan

 

Someone once posted that the trick to an accurate measurement was to leave the bike on the side stand for 10 minutes (after warming it up), which helps the oil drain back out of the cooler. Then put the bike on the center stand and take the oil measurement. Maybe it's true or maybe not, but I seem to get a more accurate measurement that way.

 

And yeah, from personal experience, I can tell you that you add oil when the sight-glass is empty, and leave it alone when there's any oil showing in the sight-glass. The difference is a couple of ounces, and if you try to be too precise and overfill, you'll end up with oil pushing past the inner rear engine seal and venting to your air box. In my opinion (as I struggle with replacing my rear engine seals, and have seen how they work close-up), oil in your air box means that (a) you've overfilled the bike with motoroil and (b) your rear crankseal is failing because of it. Fortunately, for the more recent models (or so I've read), there are now two seals, an inner and outer seal, with a vent to the airbox between the two. So, if oil pushes past the first seal it vents to the air box, and the outer seal will still protect your clutch. For the older models, there is only one (outer) seal. When oil gets past the outer seal into the clutch housing, you get to do a clutch job!!

 

Don't ask me how I know ...

 

(Actually, I haven't experienced a oil-fouled clutch failure. I'm doing a transmission/clutch job now, and just pulled the flywheel to check the outer seal. That resulted in replacing both inner/outer seals. But there was oil between the two seals, which means (in my opinion) that there was sufficient oil pressure due to overfill to push oil past that first inner seal, or, the inner seal was just going bad.)

[Stan Walker]

But there was oil between the two seals, which means (in my opinion) that there was sufficient oil pressure due to overfill to push oil past that first inner seal, or, the inner seal was just going bad

 

I disagree. Since the space between the two seals is part of the crankcase ventilation system you can expect to have some amount of oil carried there by the escaping gasses. Most of it continues on to be deposited in the airbox but some will remain.

 

Stan