Oil Level sight glass

[REFFI]

I hate to start a topic if it's already been covered. I read through the three most current pages of the forum and didn't see anything releated. My problem is: I pulled the bike onto the center stand and tried to check the oil level in the sight glass. The sight glass is totally black. No indication at all of oil level. My last oil change, as have all of them, was at the dealer and it wasn't that long ago. Has anyone experienced this problem? If so, how was it solved. I'm afraid to just add oil it the bike doesn't need it, but I also don't want to ride it with the oil level low.

Thanks for any assistance or guidance.


Ralph

[MIXR]

Ralph - This has been done to death in any number of BMW sites. However, I'll contribute the following.

If the engine has been seriously overfilled, then you can generate several problems. One common outlet for excess oil is via the airbox. Undo the drain plug (left side rear under the tank) and see if you get oil in any quantity dripping out. It is not uncommon to get a couple of drops collecting there. If that is good, then have a look at the handbook on the process for checking oil. You need to park the bike on the sidestand when it's hot to let the oil drain down. A few minutes is all that is required. Then center-stand it. The oil level should be in the sight glass, about half way or higher.

These bikes have a habit of showing different levels under different conditions with no additions of oil. There is very little difference in the oil quantity between a full sight glass and an almost empty one. They hold almost 4 litres of oil, so 250 ml is nothing to be concerned about. If the bike is now 'full', just tilt it slightly to the right without dropping it and see if you can see oil. If the level is there, but just over the top, it will be just fine.

A lot of people run these bikes at the 'full' sight glass mark because they tend to burn down to the right level anyway. So long as it's not pushing oil outside the engine, it's ok. If the sight glass is 'black' because there is low oil, then add some. They will burn oil under some very variable conditions. Just check the level on the side stand and you should definitely see a 'full' sight glass. Slowly tilt the bike to the centre to see if the level disappears as you do that. That's an underfill. Add oil. 250 ml at a time will work, and won't give you a severe overfill. Just give the cold oil time to run down.

I have to check mine on my GSA with the bike upright and under cold conditions because I have a sidecar fitted. No sidestand. If I see oil in the glass before a ride, it's fine. It always drains down overnight and always hits the same place after an oil change where I add a measured quantity of fresh oil. Far easier than than the 'oil dance' required by BMW! You tend to get used to the level for your bike after a while. That's very different to what I did with my Roadster.

Hope that helps.

[REFFI]

I have not added oil since my oil change. I'm saying that the sight glass is opaque. I'm used to being able to see through the glass to the metal part behind it. Now it's as if someone painted over it. Physically, I am unable to try the things you recommend (at least not alone). To check my oil, normally, I put the bike on the centerstand and use a flashlight and a mirror to see the image of the sight glass.

[AndyRR]

That glass should not be opaque. Opaque = useless. You sure it isn't just overfull? With the bike on it's center stand, tip it away from you as you watch the glass. You may need a helper.
You didn't mention the oil-check dance (the only way to correctly check), but this would only make the level higher.

[Boxer]

Usually, when the oil sight glass has gone opaque due to excessive heat, the opaqness is a dull light gray or white color...not black. This is a new one on me.

Follow the above directions by looking as you tilt and see if you see anything then.

You may have inadvertently started yet a new and unique oil thread! Quite an acheivemant!

[MIXR]

There are a few things that can lead to a sight glass going 'cloudy'. One is apparently heat, but I personally don't subscribe to that as I have run my bikes in some very hot conditions and not had an issue. I guess idling in traffic could generate enough heat to damage the sight glass, but doubtful in my experience. Another is the continued use of 'old' oil, where the additives break down and the oil itself starts to generate corrosive residues that can attack the sight glass. The other is through long-term mixing of oils, where you get a chemical reaction between oil packages (the oil and oil additives used by different manufacturers), thereby creating a sludge that can coat the inside of the sight glass. Either way, if it's a cloudy sight glass issue, you either live with it or replace the sight glass. Remembering of course that the 'glass' isn't glass.

[REFFI]

Thanks for the posts. If someone could, please, direct me to the "oil-check dance," I'll get SWMBO to help me out. An overfill should not be part of the equation, unless the dealer committed a bonehead error.

I'll post further as more information develops.

[MIXR]

This is out of my R1150R manual. My R1150GS manual is the same process.

The 'dance' is usually for hot checking. I explained this in my earlier post. Sidestand for a few minutes (5 is what is often quoted), then centrestand. The idea is for the angle of the bike to allow hot oil to flow down from the coolers. For me, that's all poo. The oil will leak-down overnight, so I always check mine when cold. Next morning or an hour or two after a ride is usually ample. If I can see oil in the glass, it's good for another day's ride. For me, that's often 1,000 kms or more. 200,000 + kilometres and never had an issue. If a 'cold' check is good enough for BMW, it's good enough for me.

I know when I do a service that I put in 4 litres. I know if I can see oil in the glass it has enough. There are times with my GS when the oil does burn down a little, so I top it up to the top of the glass. That's rarely more than 250 ml. The oil useage is sometimes an erratic thing, particularly on my GS. The R was good - It used none between services each 10,000 kms. Do the 'dance' if you want, or just check the level before each day's ride or after it's been sitting on the centrestand for a few hours. Up to you. Others will have different opinions.

[AndyRR]

For me, the simple dance was to put it on the sidestand when I park it in the garage at the end of a ride. The next day I ride, I put it on the centerstand as I'm getting suited up, then check. It's mostly about consistency. As I became used to the oil consumption, or lack thereof, I checked less often. I'm sure that most of the oil will drain down either way. I forget the origination of the dance. We BMW owners can be fanatical about the details.

[gregor]

Been away for a while in Washington DC. Not many BMWs or other bikes there. Except for Memorial Day when the Harleys suddenly appeared.
I'd drain down a litre of oil or so to check if the engine was overfilled. If the glass is still black then you do have a new type of problem.
Brownish oil yes but black is usually only found in diesels. My new 20/50 oil is clear enough to see right through it.
Good luck.

[DMM]

Wondering if you're only checking the oil in the sight glass after rides. If you aren't giving the bike a chance to cool off and the oil to settle, then you won't get a reading from the sight glass. If you've been letting it settle and cool off, then I'd guess that there is too much oil. As mentioned by another above, a cloudy sight glass shouldn't look black. The only time I'd seen that was when I'd put it just a tad too much oil in the bike. Removing some oil was the fix.
Cheers

[riceburner]

Old oil will make the sight glass appear black (especially the castrol Mineral).

I'd suggest leaning the bike to the right - against a tree or wall would do, when cold. if the sight glass is STILL black then you may have an issue, but it's clear (and the back plate is visible) then it's just a bit overfilled.


Alternatively..... clean the thing!!

[psychodeathbot]

If it's black, the oil level is probably above the top of the glass and what you're seeing is dirty oil. You can test this by draining a little out of the engine and seeing if the level goes down.

Overfilling has the potential to do a lot of damage, particularly if oil slips past the rear main seal and fouls the clutch friction plate (DAHIK). BMW twins have an automotive-style dry clutch and getting any oil on the disk will ruin it. If you are using synthetic oil, it will not typically "burn down" to the correct level fast enough to avoid the risk of fouling the clutch and although the oil engine oil capacity is technically four liters, you will rarely if ever put in that much during an oil and filter change. To check the oil level, ride the bike long enough to reach operating temperature then park it on the sidestand and let it sit for at least 15 minutes before putting it on the centerstand to check the level in the glass (on a level surface of course).

Replacing the oil level sight glass is usually pretty cheap and easy. Ordinarily, I use a small, pen-style soldering iron to melt a hole through the plastic and then punch a small hole in the metal backing with an awl. Then I drive a 2-3" wood screw and using a 2x4 to protect the cooling fins, pry the old glass out. The last sight glass I replaced was very stubborn and this method did not work. In the end, I had to use a seal-puller to finally pry that SOB out. You'll need a drift such as a 21(?)mm socket to tap the new one in being very careful not to let the drift slip on to the plastic. I'm thinking the next time I will use the soldering iron to perforate the plastic in such a way as to remove it completely intact before going in with the seal-puller. It's far too easy to crack the plastic and risk getting shards in the engine.

Hope that helps,
-Erik

[Dr. Strangelove]

Does anyone ever replace the sight glass prophylactically? IE before it breaks?

Does it ever rupture while riding, under routine circumstances? If so, does your oil get pumped out of the crank-case with "extreme vigor?" Will the OIL light go on?

Is trauma to the glass required for breakage, or do they all eventually weaken and give out? If the latter, what kind of mileage is involved?

There was a thread a while back about using a black rubber stopper to plug the hole if this happened while on the road. Anyone ever do this? does it really hold? Does it melt/burn?

What size stopper was rec'd, anyone remember? 30mm seems to sound familiar???

something else to fret over

[psychodeathbot]

I seem to recall Paul Glaves recommending preventative replacement every XX,XXX miles, but I can't locate the thread. I replaced mine at 40k...others have said that it will weep before it blows.

[Sunbeemer]

Yes, I've heard of sight glasses blowing out underway which is accompanied by a "chuffa-chuffa-chuffa" sound that is like the sound heard while running your engine without the oil-fill cap installed. If you have never done that it might be a good idea to familiarize yourself with that sound in case you ever hear it to know what is causing it. WTF

And when it goes it blows oil all over your right boot.

Fortunately there is usually some warning in the form of oil seepage that often appears around the outside of the sight glass before it fails. Look closely around the circumference of the oil sight glass for any sign of oil, and replace it prophylactically if noticed.

Finally, you could make a roadside repair using a temporary engine-block freeze-plug. It is a rubber cork sandwiched between two large washers with a bolt though it that can be tightened once inserted in the hole to expand the rubber and seal it in the bore. It should work very well, but you won't be able to check your oil. You can measure the size of the hole the sight glass is mounted in and buy one to fit at an auto parts store.

Oh, and by the time your oil (idiot) light comes on, your engine is out of oil and the damage has pretty much been done, thus the term "idiot" light. Try to shut off your engine as soon as you hear that "chuffa-chuffa-chuffa" sound. The faster the better.

[Dr. Strangelove]

Thanks, Rich

you mean your left boot, correct?

something else for the carry on kit.

[r1200rclassic]

generally speaking, after you start a cold bike, how long does it take for the oil level to drop on the sight glass to the bottom where it normally sits when the engine oil pressure is stabilized? I've heard up to a minute, is that right?

[Sunbeemer]

Right, left!

[Ol' Jeffers]

Thanks, Rich

you mean your left boot, correct?

something else for the carry on kit.

Cut the guy some slack, Doc!! I mean...he does live in Florida!