Leaking Oil Filler Cap

[Laserr Boy]

My oil filler cap has developed an annoying leak that was not cured by replacing the o ring with the genuine approved item from the genuine approved dealership. I seem to remeber reading about a cure someplace but I can't seem to find it again. I have also seen a couple of different styles of aftermarket filler caps and at this stage I do not even care how much it costs to cure, just so long as the product will actually keep the oil in the engine. Has anyone out there used an aftermarket product that works and if so which one ???

[boxermania]

Make sure the "base" (the part that is held in the head) is clean, the o-ring is OK and is fully seated. The o-ring in the cap should be clean and not damaged in any way.

[MattPie]

My oil filler cap has developed an annoying leak that was not cured by replacing the o ring with the genuine approved item from the genuine approved dealership. I seem to remeber reading about a cure someplace but I can't seem to find it again. I have also seen a couple of different styles of aftermarket filler caps and at this stage I do not even care how much it costs to cure, just so long as the product will actually keep the oil in the engine. Has anyone out there used an aftermarket product that works and if so which one ???

I have a moto techniques cap. Not bad, although i think I have tighten up the set-screws. It turns a little bit when loosening the cap after I had it in the shop. I think the shop may have cranked it down a little too tight.

http://www.amazon.com/Moto-Techniques-5 ... 78&sr=8-25

The install wasn't too bad, although it took at bit of rubber mallet and dowel for me to get it pressed into the valve cover. The only other annoyance is there's a little plastic cap that covers the hex-head hole in the top that I've already lost. The only issue with that I suppose gunk could get in there and I'd have to clean it out before I could get the allen wrench in there. It comes with the little allen-head key chain thingy that's sufficient to get the cap on and off.

[citrusbbee]

I had the same problem last year. Replaced the o-ring in the cap, but that did not solve the problem. I found out that there is a lower o-ring also. When I replaced that one, problem solved. Just had to use a screwdriver (carefully) to pry up the part that the cap sits in, which is also where the lower o-ring is seated.

[taosports]

Buying an aftermarket oil filler cap won't necessarily solve your leak. Just replace the entire oil filler assembly. Will cost you less than $10. for parts 5,6,7 and 8 below.

[Laserr Boy]

Thanks for the replies. I have replaced #'s 7-8 on the drawing and that has slowed the leak to a slow trickle. The aftermarket cap setup that I have been scoping out is the same one MattPie used and it looks the same as the ones in Mr & Mrs Sweatmarks bikes. There are other caps on the market but all they replace is #'s 7 & 8 and it seemed to me the only way to stop the weeping would be replacing all of the components. So far this is the only aftermarket solution that I have seen that replaces everything.

[jas]

Have you tried replacing the lower o-ring yet, #6? When mine was leaking, I put a couple fingers in the throat (whatever that thing is called, #5 in the diagram), pulled it out, cleaned the area, replaced the seal and then part #5 which only goes back in one way.

This appears to have worked very well and set me back a dollar or so for a couple o-rings

[Ritchard]

Cleaning part 5 of grit and such, plus replacing o-ring part #6 should go a long way toward alleviating your problem. I found that my 0-ring had become quite deformed when I last replaced it. It was compressed into a wedding band like shape, instead of a nice thick donut shape.

Once I had replaced 3 parts (6, 7, and the filler cap fits nice and snug, and no more leaking or seeping oil. Total cost like 10 or eleven bucks.

[Buckster]

Thanks for that diagram Micheal. I have just started getting a little oil around the cap and wasn't aware of that second o-ring until someone mentioned it. Now I know where it is. Thanks!

[Kobe22]

Since we are on the subject of oil leaks I thought I'd post this here instead of starting another thread. I observed a thin film of oil at the bottom of my engine. I'm the second owner of the bike and you'd observe from the picture that the original owner changed all the bolts to titanium luminescent green bolts, I liked the idea until I noticed this <table style="width:auto;"><tr><td><a href="http://picasaweb.google.com/lh/photo/gR ... site"><img src="http://lh6.ggpht.com/_znkYmF1MSjA/TA2eY ... 6-1408.jpg" /></a></td></tr><tr><td style="font-family:arial,sans-serif; font-size:11px; text-align:right">From <a href="http://picasaweb.google.com/Kwabenaemma ... tr></table>

Now I'm wondering if perhaps the bolts were not installed to the correct torque....

Any ideas would be hugely appreciated since this is left a slightly bitter taste in my mouth... Oh, bike has 4000 miles on it... yeah four thousand on a 2004 bike, the original owner was a really nice Surgeon who I'm guessing didn't do a lot of riding...

[Kobe22]

I guess I'll try the image again.... http://lh6.ggpht.com/_znkYmF1MSjA/TA2eY ... 6-1408.jpg

[jfslater98]

Yuck. Let's hope it's just the bolts need to be retorqued. I am guessing they're M8s, so by the picture below, that's 20nm. I am hoping it's not "clean, degrease and apply 3-bond".

Good luck!

[Kobe22]

Hey Slater,

U rock! Thanks for the quick response... yeah I really need to get me a manual for this thing... Since it's just about 2000 miles to the 6000 mile service I was gonna chug it along till then, while of course keeping an eye on the oil level indicator. Would you counsel this or no?

Also I was gonna clean it with some engine cleaner and see if the film re-appears and at what speed since I'm guessing that should be a fair indicator of the level of damage....

Hear's another shot...

[jfslater98]

Lots of cheap sources for the R1150R manual. I got mine on ebay, after a couple tries. Don't ask. If you poke around the interwebz, you can find it for free sometimes. The manual is good for looking up stuff like this, but it's not very good (imo) in leading you through any kind of procedure, such as adjusting the valves. And the ABS flush is non-existent. But the ne plus ultra of ABS flush procedures is right here on this board! It's even better than the one on ADVrider.

And now it's time for me to stand on the soapbox: don't forget to donate to this board. You can do this one of two ways: click on the ads at the bottom of the page. Or outright Paypal Doug some bucks. This site has saved me thousands of dollars over the years, so well worth it.

[off soap box now]. Anyway, doesn't look like too bad a leak, but definitely worth watching. Good luck and keep us posted.

[DKSTRWER]

Agreed that even replacing the entire oil fill cap assembly with new OEM will not solve this design flaw for long. Some techs do use a sealant around the base when installing a new one with success. I particularly like Permatex High Tack Gasket Sealant item #80062 as it does not harden. Even silicone has been proven to leak. Use it also on the 11 12 1 341 873 cover (back side of cylinders, oval shape, 2 bolts) as those also have a strong history of seeping. In all cases clean surfaces well.

[riceburner]

As long as the sealing areas are VERY clean and dry when the seals are installed - there shouldn't be any leaks. I never get any leaks - well - I had a minor one, but replaced the entire assembly and now - nothing.

[kirby]

The cap on the oil head is not a design failure IMO. The BMW folks are trying to save cost by using a plastic component which is done throughout the auto/moto industry. The OEM cap will last 23Kto 35K before starting to weep oil. This is from 275K miles of my experience with the oil heads.

Frankly few people put more than 15K to 25K on their bikes. Those that keep these machines for the long haul (180K on my '04 rockster) need to understand the stress that is put on the cap during normal ops. Take the plug out and start the engine and you will be astonished at the pos and neg pressure that is slamming against it. It wares out getting hammered up and down. The configuration of the engine and fairly large cylinders produce ALLOT of crankcase pressure.

So long timer owners need to replace the assembly with a metal one and the problem is solved. I use the wunderlitch one.

[Kobe22]

I changed mine out this morning (it was bleeding oil all over the left side of the bike); the piece that locks into the bike itself. I did it after morning mass in the church parking lot - 15 minutes tops! I don't even know why people suggest taking off the valve covers, no such thing is required or necessary. Remember to clean the mating surfaces.

A bit of elbow grease and it comes off in one piece; oil the new O-ring slightly and push it back it. No leakage since. Thank you guys for the awesome support.

[Shinnyhead]

Try the Wunderlich Drysafe Oil filler cap. I just ordered one. Had to do a stack load of searching though. There is a youtube video that explains how it works: https://www.youtube.com/watch?v=f9hpQzICZWA