White Oil Sludge?

[LumpyCam]

Doing an oil change I noticed a creamy goo-sludge under my oil fill cap. I had noticed it before at various quantities on previous changes but today's was the most i've seen. On one previous change I was convinced i spotted some on the inside of the sight glass too but it's hard to be certain. The oil that drains out of the bike appears normal. Oil is Motul 20w50 mineral.

Anyone know what this is or experienced something similar?

[Bob Ain't Stoppin']

Lumpy, What you're looking at is moisture condensation. I'm gonna guess that you are using the bike for short trips so it doesn't have a chance to get up to full temperature and boil off the water. Go for a long ride and this should all correct itself. The problem is more likely to develop in cold weather when the air cooled engine can't reach full temp.

[mogu83]

I'd second that, but I never saw it that yellow color usually it's more white.

[LumpyCam]

What you're looking at is moisture condensation.

That diagnosis makes perfect sense - I do drive the bike short distances on the daily commute and these days it is very damp and always hovering around freezing so there is tonnes of moisture and condensation.

Thanks, Bob & Harry!

Dan.

[creamora]

Ditto here Lumpy - I got my first taste of the white sludge warming up my bike a few weeks ago in the garage. Got a little cloud on the sight glass too. Trying not to freak out too much and holding out for warmer weather.

To the Elders - Is this something to avoid (long term effects inside the engine case?) or character trait #536 of BMW Boxer ownership?

[mogu83]

Not much you can do about it except get the oil warm enough for the water to boil off.
I don't seem to have as big a problem with condensation with synthetic oil but that could be because I rarely use the bikes for short trips. One of the benefits of being retired - if it's nice enough to ride the bike it's nice enough to take a long ride - and I have the time.

[LumpyCam]

Another challenge this time of year is while it is safe enough to ride, the roads are a bit slick for the usual "bounce it off the rev limiter" style I'm usually guilty of. So not only are the distances short, the riding is tame and the engine never sees much over 5k rpm.

[sky_sailor]

Lumpy, What you're looking at is moisture condensation. I'm gonna guess that you are using the bike for short trips so it doesn't have a chance to get up to full temperature and boil off the water. Go for a long ride and this should all correct itself. The problem is more likely to develop in cold weather when the air cooled engine can't reach full temp.

BINGO
We used to have that happen in old round aircraft engines all the time. No worries mate, just let her get good and hot, and she'll boil off the moisture. We even used to "dilute" the oil by injecting some fuel (gas) into it. Then, in the morning, we'd run the engine for about 45 minutes to "boil off" the gas.
Cheers

[ContraMoto]

On a related note...how hot is too hot for these motors? How many bars on the temp indicator is too many? Mine has only gotten up to the first hash mark on the left scale...I think four bars above the big bar at the bottom. Then again, it's not been above 55 degrees out since I got it...

[deilenberger]

On a related note...how hot is too hot for these motors? How many bars on the temp indicator is too many? Mine has only gotten up to the first hash mark on the left scale...I think four bars above the big bar at the bottom. Then again, it's not been above 55 degrees out since I got it...

Anything under the second hash mark on the left is fine. Midscale between the two is around 186F for oil temps (checked with the GS-911..) I've never seen mine more then 3 bars over the bottom hash.

[dbrick]

On the way home after buying the bike last September, significantly uphill on Highway 17 for about ten miles, I saw one bar over the middle hash mark. The day was warm enough (above 90F) that it took the whole other side of the hill for that bar to disappear.

[tinytrains]

Mine normally alternates between the middle mark, and one bar up. Even stuck in traffic, it has not gone higher. Amazing for no fan.

Scott

[NakedRider]

Mine usually runs one bar above the middle mark.

[sky_sailor]

Mine usually just goes to the bar. On occasion, I've taken a cab home from the bar....
Lyle

[racerb]

The moisture dilution normally would not be a problem EXCEPT that bikes tend to sit for long periods and the condensation stays long enough to damage some Wear surfaces. You really need to boil this stuff off often. In fact in the automotive world the transmissions condense a lot of water in cool climates so one of the ways to deal with it is the oil to water cooler in the radiator. While it does lower the temp of the tranny when in a summer up hill tow, the most important thing it does is raise the transmission temp to 195*(coolant stat setting) during the winter to boil off the condensation. Many new pickups also use an engine oil cooler that uses coolant as the heat sink or heater depending on the conditions to maintain a 200* oil temp under all conditions. A procedure I use when riding in cool climates is to block the oil cooler with cardboard. Get the temp up to 3/4. Just don't over do it. And change the oil more frequently as you will also get fuel dilution from the overrich condition caused by low ambient temps. Our injection systems tend to run too rich for way too long in cold climates. Most likely not a lot of time(money) was spent on mapping for conditions that few ride in. Not a problem but something that must be delt with.

[LumpyCam]

In follow up I started doing a longer route for my commute (any excuse to log more miles is welcome), about 25km, and hoped that would prevent the moisture contamination. I did an oil change to 10w40 too for the cooler temperatures. Sadly, when i checked recently the moisture contamination was still there.

So i rigged up a barrier for the oil cooler to help the oil temp get up and burn off the moisture. I logged about 70km and checked the oil again and it seemed to have worked burning off the moisture. Note the outside temperature was just around freezing and the oil temp indicator still rose to one bar above average so i don't recommend it for much hotter weather.

Rig something up to block the heater:


And the oil looks cleaner.


Problem solved - at least temporarily.