Oil Levels Affected by Thermostatic Control?

[gregor]

Sorry if this is going over old ground.
After over two years of ownership I was in a panic yesterday, over my oil level on the R1150R. Always allowed bike to sit for some hours on the centre stand before checking levels, being aware of all the problems.

But, suddenly, the oil level dropped from middle of the window to the very bottom of the sight glass after a coolish and wet journey of 25 miles. Bike had sat all day on the centre stand as well.
Putting it on the side stand showed oil was there- indeed then it covered almost the whole window. Rode home and then put bike on main stand. After 15 mins, level was back in the middle of the window.

Weather was much hotter going home - so was a thermostatic valve then open allowing oil to drain out of the oil coolers?

[Rootin55]

Yes, maybe Cycle Rob will add his expertise but I want to say the thermostat opens at about 180F. The bash I went to in NC had us riding back to Houston in terrible rain all day. As usual, I check the oil level after a long ride, assuming things are heated up well enough to allow the oil to run down from the "open" thermostat. I was almost 1/2 quart low and added the required volume to get half way up the glass. The next day was clear and upon checking after that days ride, I was all the way to the top of the glass. Even though we had ridden 500 miles plus the day before, the rain kept the oil to somewhere below the temp required to open the thermostat, thus the false reading. Hope this helps.

[Airman]

Sorry if this is going over old ground.
After over two years of ownership I was in a panic yesterday, over my oil level on the R1150R. Always allowed bike to sit for some hours on the centre stand before checking levels, being aware of all the problems.

But, suddenly, the oil level dropped from middle of the window to the very bottom of the sight glass after a coolish and wet journey of 25 miles. Bike had sat all day on the centre stand as well.
Putting it on the side stand showed oil was there- indeed then it covered almost the whole window. Rode home and then put bike on main stand. After 15 mins, level was back in the middle of the window.

Weather was much hotter going home - so was a thermostatic valve then open allowing oil to drain out of the oil coolers?

gregor,

My experience with my `03 is that the longer it sits, the lass likely the oil level glass will tell you the truth. I check it hot. I put it on the side stand for a few minutes to drain the coolers, the pull it up on the center stand and check it in no more then a half hour. There's no panic if you see oil in the glass. You must still have, what, three quarts left in there ?

[boxermania]

gregor......adding to what Rootin 55 stated.

Sometimes the ambient conditions, somewhat on the cold side, do not allow the thermostatic valve to open allowing the oil to go throught the coolers. Likewise this will happen if the ride is particularly short.

In any event it is quite possible, under the right set of circumstances to trap some of the oil volume in the oil cooler(s) loop resulting in a low oil indication the next time the oil level is checked.

If your bike is at the stage that the oil consuption has been curtailed, ie broken in, and you see a good level prior to riding where the next day you see a low level do suspect that the above has taken place. I would add a little bit to see the level in the window, but no more and then give the bike a good run and check the level afterwards....it should be OK.

Just my 2 cents..........

[KHaynes]

The thermostatic valve certainly inhibits the oil from the oil cooler returning to the bottom of the crankcase. The only time you should check the oil is after the oil has reached full operating temperature which is about 105-110C (220-240F).

[Smoothrider]

Where is the thermostat? I've scoured the parts fiche for it. The only one I've found so far is on a R1100RT.

[Philbie]

The thermostatic valve certainly inhibits the oil from the oil cooler returning to the bottom of the crankcase. The only time you should check the oil is after the oil has reached full operating temperature which is about 105-110C (220-240F).

once it's reached that temp, would it be safe to say that checking it within the first 15 mins after stopping would be a wise idea for a more acurate reading?

[Smoothrider]

Where is the thermostat? I've scoured the parts fiche for it. The only one I've found so far is on a R1100RT.

Found it I think Top right of the engine and described as expanding element. It has the supplement 95CEL against it which I guess means it operates at 95 Celcius.

[CycleRob]

Smoothrider,

There are 4 pics HERE (and pics number 28, 29 & 30 after it), that will give you a better idea of what it is.

As was mentioned, that thermostat is responsible for almost all the panic and resultant overfilling of the OilHead engine's oil.

If the valvecover is instantly, finger untouchably hot, the level is OK to, level road, centerstand check 15 minutes+ later. In cold weather or short trip riding, you can elevate the oil temp by using the gearbox to keep the revs above 4,000 for the last 3 or 4 miles (4.8 --- 6.4km)

[Smoothrider]

Cycle Rob

Thanks - very informative.

[NHighCotton]

This is something that has got up my crawl.

New owner here and read the manual, 1st oil change, drained it hot and overnite, added new filter and should deposit 4qts per manual.
Surely the Thermostat was open when I began draining...unless it needs to rest on the sidestand before being put on the centerstand...which I think I did.

Dumped it in and took off riding the next morning, stopped to check and whoa, overfilled, I mean completely covering the sight glass.
Why is that, will it hurt?
Drained it out and re-filled with 3.75qts, still shows it full to the top of the sight glass when hot and after sitting on the sidestand.

This shouldn't be that diffcult, my former K75 didn't have this problem/issue.

Where does the overflow go....or does it just burn it off?

[larry]

I usually just drop the centerstand and check it in the first couple of minutes. I've never noted any significant increase in level after 2-3 minutes. Sometimes it does show empty, but that's when you have to give it the "holy poo" test.

-was it full last time it stopped?
-did it leak 2 or 3 ounces (it would be pretty obvious if it did)
-did it burn 2 or 3 ounces in 100 miles (again, it would be obvious

Then don't worry about it, check it next time. The best protection against a false empty is to check it almost every time you get off the bike. In the time it takes you to remove your helmet, it should already be over the lower line.

As Dennis on the BMW site says "Don't worry about the oil and ride"

[BillC]

Funny how my V strom ain't got that problem. WFC '03R

[CycleRob]

Overfilling after an oil change only happens because:

1) Engine was not hot enough to fully open the engine mounted oil cooler thermostat before the oil was drained.

2) The "Tech" added 4 full qts instead of the 3.75qts that will always bring a hot drained motor to oil window center red dot.

Because I avoid short trips and go the BMW scheduled 6,000 miles on it's full synthetic oil, I feel the need -and- have the time to go the extra mile at oil drain time. What I do is carefully remove the top right oil cooler rubber feed line and, gently, insert a low pressure regulated air blowgun into a loosely added cooler pipe connector hose to fully purge the coolers. That, followed by tip draining the bike on the centerstand and setting each centerstand foot down on a strong-n-thin 14mm combo wrench (alternating several times) . . . to safely maintain the tilt for several drain/drip minutes each time. These (for most people) crazy extra steps net about an additional 1/2 cup of nasty looking mocha fudge liquid, no doubt created and purged by the shop air. The new oil in the window afterward stays bottle clean looking even after weeks of riding. THAT makes me smile. It's not for the inexperienced as you can/may/will crack/bend/collapse the ($$$) radiator cooler pipe and/or chew/tear the rubber cooler hose. An easier way would be to remove the engine mounted oil line and add the purge air to it there. Be prepared to clean up an oily mess & replace that fat O-ring every so often if you do.

To answer your question . . . No, I do not stay awake nites thinking these things up. It's kind of obvious if you look at the gravity drain unfriendly up/down routing of the cooler hoses -or- the flat bottom of the engine's oil pan -and- can "see" the nasty old oil trapped in there. Getting it out is easy after that.

[gregor]

Thanks to you all for the explanations. I guess the UK climate is variable enough to cause great confusion. Recently in the UKs 'heatwave' it has become very noticeable that the oil coolers can get hot when opening the helmet visor at a standstill.
On my old K75 the electric fan rarely started up but when it did the blast of hot air was amazing!