Pans; oil pan gaskets; oil pan engine threaded holes, oil capacity; dipsticks;
oil pickups; WINDAGE, etc.
© Copyright, 2014, R. Fleischer
Hint: Using a SMALL offset 10 mm box end wrench or a SMALL square drive wrench with a 10 mm socket, try tightening the 14 pan bolts, but not over 85 INCH-pounds (I use 78 in this test, as seen later on). If any of the bolts have bad threads, note which ones, mark the case, so you can fix them after the pan is off.
(You don't want to replace the pan gasket and then find you have bad threads at any of the 14 threaded holes)
HINT: If the drain plug is frozen and cannot be removed, try heating it and using a Vice-Grip pliers. If no luck, find a Torx bit that is just a bit bigger than the hex hole. Hammer it into place and unscrew. AVOID any type of screw extractor, they are hard, brittle, and will cause a problem if they break in the drain plug.
|NOTE CAREFULLY: A VERY high percentage of the time when a pan gasket seems to be leaking, it is NOT the pan gasket, but the leak is from someplace else. When the gasket does leak, it is usually due to over-tightening and/or IMPROPER tightening (sequence) or damaged sealing surfaces. Leaks from the timing chest, head gasket, cylinder base area, and pushrod seals, ETC. are often found to be the cause with careful inspection.|
I am NOT a believer in the aftermarket-available soft silicon rubber gaskets...too many problems...although SOMETIMES they do work.
You will need a brand-new pan gasket. The early cork gaskets are no longer available and tended to leak anyway. The presently available gaskets are a fiber material, and are much better. They have a side with writing on it, that is SUPPOSEDLY coated with a heat-activated glue. That side is UPwards. NOTE: Gaskets have apparently been seen that do not conform to this....so just install the gasket in the correct fitment direction.
There have been instances of annoying leaks from the bolts relatively below the oil canister area. Use NON-hardening Permatex Form-A-Gasket on the bolt threads and on the washer.
FIRST check that all of the bolts CAN be tightened to 78 INCH POUNDS; if any are stripped, fix with Helicoils before further work. The absolute limit is 96 INCH-pounds, via factory highest specifications (it varies with year, model, and the particular literature), but I highly suggest you do not go that high.
Clean very thoroughly the pan and engine surfaces. Use a fine file if you have to on the EDGES on an angle if any have metal sticking up proud of the surface....I have seen people use screwdrivers to get a stuck pan off, and gouge the metal, so clean it up if need-be. If any deep gouges are found that are really BAD, clean them and apply a two-part epoxy and when fully cured, file very carefully to be flat. This is particularly important if any of the gouges are over 50% across the surface.
IF...and only IF...you have had oil leaks that you have been unable to fix by replacing pan gaskets in the past:
Use Permatex Form-A-Gasket, NON HARDENING TYPE, on the CLEAN, NON-OILY surfaces. Use a thin coating, coat 100% the surfaces. I use my fingertip to apply. For the bolts that are below the oil canister area, COAT the bolt threads and the washers with the same Permatex goop, before installing them. Sometimes leaks occur there and this will 100% stop them.
Torque all the 10 mm head bolts in an even cross-wise pattern. The cross pattern is very important to avoid bunching-up the gasket. Do the torquing in stages....start very light, criss-cross; then another similar round, taking up the torque each time. For the final torque: Torque to 65 inch pounds.
Wash the lower part of the engine and pan with a good evaporating solvent, if not already done so. Get the pushrod rubbers area, cylinder base areas, etc.
Go for a 10 mile minimum ride. BLOW a bit of talcum powder on the areas. No leaks? GOOD! Now, with engine still hot, check the torques, and then again when the bike is cooled. I typically go to 72 inch-pounds.
NOTE: BMW has shown various specifications for the pan mounting bolts. Some literature shows 8.7 FOOTpounds; some 6.5-8.0. I believe that 6.5 should be the absolute maximum; although I have shown higher for initial testing. Thatís 78 INCH-pounds! If you do not do staggered criss-cross tightening, you will bunch-up the gasket and IT WILL LEAK.
My NORMAL PAN GASKET REPLACEMENT METHOD IS AS FOLLOWS:
I do not use silicone pan gaskets....nor ANY type of sealant, silicone or otherwise, on the pan gasket surfaces (that means engine and pan metal surfaces). I make sure the pan is flat, nick-free, and install a STOCK gasket, on very well cleaned surfaces (some gasket remover products work pretty well, if you are leery (and I suggest you be VERY careful anyway) of using sharp tools in cleaning off any old gasket and sealant residues.
Any sanding of pan surfaces MUST be done on a FLAT surface, such as an old piece of window glass or a real Surface Plate. I use even pressure, and figure-eights, varying my hand position, etc. Don't do sanding unless there is a problem. You can use a lamp or flashlight at the pan-to-flat-plate surface to see any problems...or, as I do, with a very thin feeler gauge (.002" happens to be the one I use).
After the pan is known to be flat and without serious nicks (DO NOT nick with your scraping tools!), and ALL old gasket crap is removed from engine and pan surfaces, and the surfaces cleaned (I use ACETONE on a rag), I install conventionally. I hold the pan and gasket to the engine, then fingering-in all the bolts first. Sometimes I hold a 10 mm socket in my fingers and just go finger tight. Then I tighten evenly, in a criss-cross-pattern (very important), and for the first go-around, I use a quite low torque, just by feel, I'd guess at maybe 10 INCHpounds or so, never have measured it. I might use the socket and a 4" or so stubby square drive tool; or a box-end wrench..
Then, I almost always just use that small 10 mm box end, offset, wrench. If you do not have a good feel for torque, use a good INCH-POUND or equivalent torque wrench, after you get all the bolts evenly and LIGHTLY tightened. Always do any tightening in a cross-pattern...this is just plain good practice, and is IMPORTANT at the pan. It is very important to torque evenly, in a cross-pattern, and to do this in STAGES. That means any one amount of torque number is done in a back and forth staggered cross-pattern until all bolts are at that torque level, then increase the torque a bit, until all are at that next level. The idea is to NOT 'bunch up' that gasket. Of course, the idea is also not to over-torque the bolts and pull threads out of the engine!
Do NOT!! use a big torque wrench like we use for
swing arm locknuts or for the cylinder stud nuts. The torque values for the pan bolts are in INCH POUNDS, not foot pounds....many have made a mistake, and it will cost you!
After you have ridden the bike some, and have a few heat-cool cycles, you can re-torque the 10 mm bolts. If you find any leaks at any given bolts, you can remove the bolt and apply some common gasket NON-permanent sealant at the BOLT threads and under the bolt (and washer) head. I prefer the Permatex NON-hardening Form-A-Gasket product.
In general, it is wise not to exceed 82 INCH-pounds.
Torque Wrench Conversion Factors
There are articles on this website about torque readings, wrenches, conversions, values, etc.
For the purposes of the pan bolts, you may have reason to
convert values for various types of torque wrenches.
ONE Inch-Pound is the same as 1.1525 CmKg and also same as 0.1129 Nm....and
1/12th of a FootPound. Use an inch-ounce torque wrench if that is
what you have. DO CONVERT PROPERLY!
Common torque wrenches with maximum's of 75 or 100 foot-pounds are NOT ACCURATE for the pan bolts. Trying to use a FOOT-pound wrench is usually BAD, as you are typically at the bottom of the wrench scale, even if it does go that low. Remember, 72 INCH-pounds is the same as 6 FOOT-pounds! Metric-reading torque wrenches are much more commonly seen in the USA nowadays. Small capacity metric torque wrenches are available, in various types of readings. One such is cm-kg, and 83 cm-kg is same as 72 INCH-pounds. Some wrenches read in both metric and American standard. Be cautious. A common 75 or 100 FOOT-pound wrench might have Nm scale readings, and the SAME problem occurs when trying to use small settings, whether metric or standard, that is, 72 inch-pounds is only about 8 Nm. I very much recommend you do NOT use a 75 or 100 foot-pound wrench to tighten pan bolts!
Bad threads are best fixed by installing Helicoils. You will want the M6 x 10 Helicoil kit.
You will need a 1/4" drill bit, unless your kit comes with the drill bit. YOU MUST drill and tap at 90 degrees to the surface. USE A DRILL AND TAP GUIDE(s). If you drill and tap on an angle the results often are 'it leaks, forever...'.
At the next oil change, drain the hot oil.
Put a large and soft towel or other item on the floor, as
the pan MAY fly off the engine. The pan may have been put on with
a sealant, which is WRONG! thus, the pan may be difficult
to remove. Occasionally even a pan that does not have
sealant applied will prove difficult to remove. Check that
every pan bolt is
removed! There are 14.
HEAT a corner area of the pan if not already hot from riding. Use a block of wood and a substantial
hammer and give the well-placed piece of wood a substantial whack
from the hammer. Do NOT bust fins,
ETC. DO NOT be stupid and allow the pan
to fly across the area and be damaged. I usually have an
assistant to grab the pan so it cannot fly.
With the pan removed, VERY thoroughly clean everything. It is critical that you do not nick the pan and engine mounting surfaces. Any projected nicks you find should be dressed flat. Rarely you may find a nick that needs filling, you can use one of the metal epoxies for that, then after curing, make it dead-flat. To remove the old gasket, if need-be, use a sharp blade on a very flat angle (nearly flat to the surface) to remove any old sealant or other substance found. Use a strong commercial gasket remover, if you wish. The crankcase surface absolutely must not have old gasket material and no nicks that have metal proud of the surface. Clean the area very well! Final cleaning of the crankcase surface should be by a good solvent that does not leave residue. I am particularly fond of acetone for this. If you have gouges and nicks that are serious, repair them. Epoxy will work OK!
Look upwards with a strong light and SLOWLY AND CAREFULLY inspect the oil pickup, etc. Be sure it looks OK and the bolts tight. This is a VERY good time to inspect that pickup, tube, casting area, for CRACKS!....some have been seen on extended pickup models. If you wish, remove the metal screen and clean it. If the two bolts for the pickup are even slightly loose, remove, clean with solvent, use new gasket(s) and apply Loctite BLUE to the threads before tightening (evenly!). If you absolutely INSIST on reusing the gaskets, and they look OK...that is, not torn, you can install them with a FAINT, but thorough, coating of NON-hardening Permatex form-a-gasket (type #2). It is preferable to install new gaskets, no goop. The reason to install fresh gasket(s) is that the gasket will not go back onto the assembly in EXACTLY the same position, and you might even have it reversed or upside down, as they fit both ways. That means that the raised area and non-raised areas no longer match-up, and you can get AIR sucking-in at that point. Thus, using an old gasket is a BAD idea, unless it is mandatory in some field situation.
Check the pan for ACTUAL flatness. Use #1 eyeball
with the pan on a piece of glass or a surface plate, and a strong
light...or a feeler gauge or both.
If necessary, place the pan on a flat piece of glass with a large piece of sandpaper, perhaps grit 320. Do careful figure eights, with evenly spread hands pressure. If you are good at it, use a long flat mill file carefully covering adjacent and cross-surfaces.... otherwise do the eights. Do just enough to be sure the pan is flat, smooth, and NO dinged edges that have protruding bits, etc. DO NOT round the pan edges, flatten unevenly, etc. It is NOT necessary to try to flatten the pan to remove every irregularity, but you want it quite decent.
Check the threaded holes in the engine case....any been drilled through into the oil area and Helicoiled...or? Is the bottom engine area FLAT?.....not been dinged by someone?...looks good around the threaded holes?
Are any Helicoils (or?) BELOW the surface...they had better be! Are the internal Helicoil tangs, used when installing the Helicoil, removed? They should be!
HINT! I have found it sometimes necessary to use a gasket sealant on the pan BOLT threads & under the heads (and I ALWAYS use waverly locking washers). My particular favorite is the old tried and true Permatex Form-a-Gasket #2...(do NOT USE #1, it is much too hard and permanent when it dries). ANY decent sealant will be OK. The most common THREADS leaking problem (but can be at other areas) is at the pan bolt holes below the oil filter area. Use a flashlight or stiff solid wire to investigate those holes, before you button-up the pan and gasket. THROUGH holes are always suspect for leaks.
use any sealant on the gasket
surfaces! The gasket writing should be UPwards!...there
is a heat activated glue on that surface!..that is, if the pan
gasket was made properly (some are reportedly not).
Hold the pan and gasket up to the engine FLATLY, and with fingers, get the 14 bolts installed. NOW...tighten the pan 10 mm bolts (with waverly washers) very carefully, in a cross fashion...bit by bit....I do this with a small 10 mm box wrench or 3/8 drive socket and short ('stubby') handle ratchet. I do it by FEEL, and I guess I do it to around 6 foot pounds...but I have seldom measured it. BUT, I DO NOT go for that full torque right off the bat. I do the tightening in STAGES, in a cross-pattern. Do one amount of tightening, then when all 14 bolts are at that tightness, increase the torque on one bolt, and start the cross-pattern tightening again. Continue until final tightness is reached. OVERTIGHTENING will cause LEAKS!...if you do not pull threads first.
Install a FRESH drain plug crush washer (or the later solid aluminum washer BMW now sells).
NOT FORGET TO INSTALL OIL!!!...yes, folks HAVE done that!
After a few heat-cool riding cycles, touch up the torque on the bolts again; again a cross-pattern....slightly.....same torque level.
Pan and pickup differences (and some other stuff):
The oil pans were not the same
over the years, and some aftermarket ones were also available,
supposedly to improve cooling, which they do not
do much of...really!
Early pans were flat. In 1976 the pan was lowered a bit, it was a bit deeper, which gave more room for crankcase pressure, and reduced oil consumption from oil mist through the breather due to that extra air space. The breather was also modified, a bit later.... it was still the round disc at that time, but added in 1978 was a tiny hole in the bottom of the oil condensation chamber in front of the breather....to drain oil back into the engine. That teeny hole MUST be clean and clear, if not, you will use oil more rapidly. When the pan was lowered half an inch or so in 1976, BMW now had to and did add a spacer in the oil strainer pickup tube, at the 2 bolts. Early spacers were phenolic, then later were aluminum. Two small gaskets are used when the spacer is used. I prefer to use a tiny amount of evenly-spread sealant like Form-A-Gasket non-hardening #2 on both sides of the paper gaskets, using my fingertip...remember, THINLY......and Loctite BLUE on the threads of both bolts. The spacer surfaces need to be flat and nick-free, and the two bolts need to be evenly tightened back and forth. Some folks have used red Loctite.
can't use the one piece cast part on the early pans; that part is
used only with the 1981+ pans. The one-piece casting versions eliminated
the need for the spacer and the extra gaskets.
In 1981, BMW made the pan a fair amount deeper, adding more oil capacity, and a slosh baffle in the pan construction, so the engine would not momentarily run out of oil on very hard braking. Also in 1981, the pickup became a cast aluminum item, no longer was a sheet metal steel pressing.
There were 3 types of oil pickup assembly bolts used, all M6, but of various lengths depending on the bike's oil pickup items. There may have been 4 types, not sure, I seem to remember one of the bolts had two head styles....one had more taper under the head. My memory might be faulty in this matter. This is hardly anything critical...the bolt must simply be long enough to fit the items properly.
NOTE: Mystic, Roadster, G/S, and GS models use a shallower pan. The pans have threaded holes for mounting a bash plate. These shallow pans are the replacement for the original NLA /5 pans. The GS pans were slightly deeper from 1991; and GS pans have a rear wall drain. There were special pans for the GS in, I think, 1988....with a large capacity.
NOTE! 1970-1975 center-stands
do not work with deep oil pans, unless you modify the
center-stand (or, change the stand).
There is even more confusion with what dipstick to use, see below.
I am NOT in favor of NON-BMW aftermarket 'oil cooling' extension items, that give a larger oil capacity and have tubes in them running for and aft. Rare, but they have been known to give serious problems. They don't add to cooling much at all.
Anton Largiader has a
considerable amount of information with photos of pans and
dipsticks. He also covers some aftermarket pans at the end
of his article.
BMW has used two 'styles' of dipsticks on the airheads. The early style was silvery, metal top, and used a metal crush-ring type of gasket (which was not tightened so tight as to crush it!). The later style has a black top, which stays cooler to the touch, and uses a rubber O-ring in a groove in the top handle.
The only good way to identify a dipstick is by the top style AND by the measured distance from the bottom flat area of the top part, to the minimum and maximum marks...and the tip.
HINT!...When removing or replacing the dipstick, AVOID bending the left carburetor throttle cable!
|YEAR and model||
to min. mark
to max. mark
|1975 R60/6, R90/6||11-5/16"||11-3/16"||10-5/16"|
|1979 R100RT, 1982 R100RS||10-15/16"||10-3/4"||9-3/4"|
|1983, 1984 R100RT||11-3/8"||11-1/4"||10-3/8"|
I did the above 1983, 1984 R100RT myself, have not personally confirmed
These were the only ones measured so far. Note that these measurements apply only to stock dipsticks.
Note: just because there is information here on measuring dipsticks, does not mean, necessarily, that you have to replace yours, if, for example, you install a later oil pan. Simply note the actual level, when you do an oil change; making sure you have the correct amount of oil for that pan.
The 1982 R100RS and the 1983-4 bikes really should be identical. I have no explanation, yet. I've not yet removed pans and checked pickup heights and oil level heights with standard oil quantities.
Following is courtesy of information from John Falconer, and
taken from a posting on the Airheads LIST on 09/06/2003 (and
corrected from mm to cm):
All John's corrected measurements are in cm, from the sealing lip to the indicated mark. Note that in the table, above, all measurements are from the flat area under the dipstick top, that is, bottom of the threads flat area.
1) Dipstick from an early /5 (metal cap, no markings) : 25.7 cm to full, 28.3 cm to low
2) Dipstick from an early '80s R65 (plastic cap with molded in "A") : 27.2 cm to full, 29.3 cm to
3) Dipstick from a '92 R100GS (plastic cap with molded in "C") : 26.6 cm to full, 28.4 cm to low
Note that Anton Largiader's site also measures the dipstick from the underside of the threaded area
There is sometimes confusion about how much oil an engine takes during an oil change. Your owner's booklet has the figures. Here are some guidelines, for stock oil pans:
Without oil coolers, up to 1980: 2.25 liters
With oil coolers to 1980: 2.50 liters
From 1981 without cooler: 2.50 liters
From 1981 with cooler: 2.75 liters
R80GS to 1990: 2.25 liters
GS from 1991: 2.50 liters
To fill the engine from the MIN to the MAX will take nearly a full liter....a quart U.S., except that after 1980 it was a bit less...about .85 Liter or .9 quart, approximately.
Unless leaving on a long tour, I suggest you have the oil level at 1/3 quart lower than max.
WINDAGE, etc: (an explanation of Windage is also below)
This section was prompted by a lengthy thread on the Airheads List in mid-February, 2014. I have edited my original reply, and put it here:
1. Review Anton's website article: http://largiader.com/tech/oilpan/
2. I have not done an article specifically on the oil pans, windage, baffles, pickups, and so on, because Anton covers it pretty well.
3. My own work, my own measurements, have proven that a deeper oil pan does give a FEW degrees of extra cooling. That is not very
important, although slightly helpful if cruising at quite high speeds for long distances, as every degree lengthens oil life (esp. dino),
especially once the oil is above roughly 230, and oil temperature also has an effect on consumption. The oil-tubes type of aftermarket
oil pans do little for cooling, although 'common sense' would seem to say otherwise. The over-all effect of a cooling tubes AND larger
oil pan is somewhat effective, but moreso is a stock BMW oil cooler setup.
4. Windage means more than one thing, in common usage, regarding oil pans and engines. There is the sudden fore-aft movement of oil
upon acceleration and deceleration; and there is the movement of oil sideways when leaning the bike over in a turn. Note the photos in
Anton's article, showing the early side baffles, and the much later cast-in forward baffle. These baffles help control the part of
"windage" that is involved with possible UNcovering of the oil pickup during sudden movement of the bike. They have a secondary
effect with frothing, etc.
5. The other part of 'windage', ......is the churning of the oil in the oil pan and above it. The crankshaft is the prime producer of the huge
amount of ...OK, call it WIND....inside the crankcase area. This wind is simply HUGE; very fast rotating too, but rotation is NOT entirely
at crank speed, it varies with distance from the crank and various friction effects of items in the vicinity. That makes it hard to control.
Just this ROTATING wind, alone, is enough to SCOOP UP OIL from the oil pan oil surface, and somewhat below the surface of the
oil...and...NO... the crankshaft need NOT dip into the oil for this! The crank whips-up the air, the rotating AND SPIRALING air is in
contact with the the oil surface in the pan, and the oil is whipped into a frothing spinning cloud. If that cloud of oil was smooth and
even, it would be easy to control. NOT SO, and not only is it rotating and spiraling, but you have the pistons moving in together and
out together. The pistons movement create a varying pressure, even slight vacuum is possible, in the crankcase.
6. There is a breather valve to help control, moderate, and release, excessive pressure.
7. Can you imagine this swirling rotating mass of oily cloud that is being ALSO squeezed (and, well, de-squeezed too) by piston
movement? The rods are nicely there to make things even worse.
8. Don't worry much about the camshaft, it is MUCH smaller in effective diameter than the crankshaft, even if placed lower....but it, yes,
contributes its own churning.
9. As in many things, distances have a big effect. In the case of the rotating crankshaft, and the oil level in the pan, the bad effects are a
square function. Thus, lowering the oil level a bit has a considerable effect. There is also a volume effect and some other things, that
would make this long response much longer, that I will avoid.
10. There are REASONS for some engines to have their oil in a separate tank, and not in an oil pan. That is called the Dry Sump system. It
can be done for enabling the engine to sit lower, for various reasons.... and it can be done for reducing, very considerably, windage
losses. Usually dry sumping is done for both reasons.
11. There are various types of friction happening with the oil cloud. Just one additional one is that the oil at the surface of the crank parts
is moving at a different speed than the oil a bit away from the crank surfaces. That in itself is a power-robbing bit of friction, much
more than you may think! Think of it as multiple friction layers. Additionally, the oil flow piles-up at various places on the crankshaft,
and thus creates FRICTION, which additionally ROBS THE ENGINE OF HORSEPOWER. In some situations, the oil is not regular and
smooth at the crankshaft surfaces, and so there is even more friction, with layers of clouds.
12. Besides these things, the frothy pan oil does not pump and distribute nicely. The PUMP finds it harder to deal with. Put another way,
lubrication is MUCH LESS. The pump was designed to suck up and distribute OIL, as a liquid, not an aerated froth. An aerated froth
is also compressible, and thus just that alone reduces volume in circulation, quite considerably actually. Quality oils contain
anti-frothing additives, but there are limits to their effectiveness.
13. A small amount of lowering of the oil level in the pan has a goodly effect on all these problems. Theory ...or, common knowledge, and
'common knowledge' is always suspect :-) has it that BMW added a forward baffle (1981?...see Anton's article), because under
some circumstances the oil pickup 'unports', which means it isn't in the oil and so doesn't pick up oil,... if you brake quite hard. Some
have said that happens more easily on quite steep downhill's. All of this is not really fully accurate, that is, it is not the full story, but
adequate enough for here.
14. It is 'common knowledge' that if you fill to the max fill line on the dipstick, you will 'burn off' (dumped through the breather mostly
unless the engine wear is enough) the initial first half quart (very approximately), much faster than any of the rest of the oil. There are
multiple reasons for this, including the windage/churning which lessens with lower levels; but also there are changes in the oil itself
over time/miles. Note also that the size of the engine determines crankcase pressures, and that the early bikes, with round breather
discs, had two positions possible on a breather post clip, and so were adjustable for the engine size. The adjustment controlled the
pressure of the spring above the disc, and more pressure (lower clip setting) was used with the larger engines which had more air
movement with the pistons movements.
Finally: There is a quite small condensed oil return hole in the breather area on later models...which should be checked for being open and not obstructed. There are photos in one of my articles of that: oilsketch.htm which will clear up confusion over where that hole is.
08/13/2006: emphasis on the glue and writing upwards
11/21/2007: WAS article 79. Minor changes in emphasis also.
01/15/2008: Move page position on Tech Index Page during re-organization of site; edit the article
for clarity during this process; add Pan Differences from the Engine Internals article.
MAJOR changes to this article.
07/07/2008: Add Anton's website link to pickups heading.
01/22/2010: cleanup, clarify some details.
03/19/2010: edit for clarity; include the LIST stuff.
02/24/2011: Changed to 50C
03/23/2011: Remove oil pan information from 50B, move here; revise this article for more clarity
04/05/2011: minor clarifications
10/18/2011: Another "C" anomalie?...make note
10/18/2011: Correct the discrepancies on the dipstick measurements, noting WHERE they are
10/12/2012: Add QR code; add language button; update Google Ad-Sense code; clean up article,
incorporate a table, etc.
02/13/2014: Add Windage section
© Copyright, 2014, R. Fleischer
Return to Technical Articles LIST Page
Return to MainPage