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Draining the oil condenser hose

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LarryZ

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Tennessee
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R18 Classic, R1150Rs, MZ SilverStar w/ hack
I have searched this title in the threads, but I do not see any discussion about what an oil condenser hose is, what it does, and how to service it as mentioned in the OM. If it is covered in a posted video, I have missed it, and would appreciate a point in the right direction. My thanks to one and all for the various maintenance info and videos posted so far -- very helpful and informative.
 
Oil condenser hose???

Are you referring to this?

BMW Airbox.webp
(#14 in picture)

It's the hose leading from the airbox that accumulates oil sucked in from the PCV. #14 is located at the bottom of the bike and is as simple as pulling the plug and letting any excess oil drain out.

Mike
 
My mistake: The OM requires "draining the oil condensate hose" (p. 175). I guess I am not 100% certain what it is and why it would require draining. The hose pictured above would appear to not require any "draining" at all; does it not just return oil to the crank case from the air box? I suppose you could say that hot blow-by oil in a vapor form is "condensing" in the air box (getting there via the PCV), and this hose leads it back home to the crank case.

I will clarify this at the dealership next month when the 6,000 mile service is completed, but having more info ahead of time allows me to ask more intelligent questions (and to better understand the answers I get).
 
My guess is the hose would contain some "condensed" oil residue that is better drained then recirculated via the intake when ever possible.... so might as well get rid of it at service time.

Fwiw.... on my landcruser.... i have removed this hose from the intake and connected it to a "catch can".... so the vapour goes through a separation filter with the fumes returning to the motor but the oil residue type "gunk"collected for later disposal.....
 
LarryZ said:
My mistake: The OM requires "draining the oil condensate hose" (p. 175). I guess I am not 100% certain what it is and why it would require draining. The hose pictured above would appear to not require any "draining" at all; does it not just return oil to the crank case from the air box? I suppose you could say that hot blow-by oil in a vapor form is "condensing" in the air box (getting there via the PCV), and this hose leads it back home to the crank case.

I will clarify this at the dealership next month when the 6,000 mile service is completed, but having more info ahead of time allows me to ask more intelligent questions (and to better understand the answers I get).
Click to expand...
The oil that gets sucked into the airbox gets dirty from the particulates that get past the air filters (they aren't as fine a filter material as the oil filter itself). As a result, if the oil remains in the airbox for any decent amount of time, it's probably just better peace of mind to dispose of the small quantity than to recirculate the dirty amount back into your system. But also, in high moisture environments (humidity does build up on occasion inside the airbox), water can also intermix with the oil, making recovery and reuse of the oil simply not worth the time.

Yes, the picture does show the drain plug. #14 is the plug you need to pull. It's located at the bottom of the motorcycle. Just imagine that long tube snaking from the airbox, which sits at the top of the engine, all the way through to the very bottom of the motorcycle. BMW made it very convenient on this bike, which wasn't always the case with previous models.

The airbox/PCV system has been a motorcycle standard for a very LONG time. Even my wife's 1976 Honda CB500t has a similar system in place. The airbox is the mechanism that SUCKS the acidic blow by gases out of the crankcase via the Positive Crankcase Ventilation (PCV) valve. The PCV valve does have a check ball that prevents liquid oil from passing through, but this doesn't prevent vapor oil - hence a necessary evil of the system (versus letting acidic fuel eat the additives in your oil, thus GREATLY reducing the life of your engine). Gas doesn't make a good lubricant, let's just put it that way ;).

So, I'll happily let the PCV/airbox "eat" some oil vapors, all in the name of engine longevity.

Mike
 
Understood, with thanks. The purpose and concept seem quite sound, but there has never been a maintenance point like this on my other bikes, hence my question.

Got a picture identifying the drain point on the bike? I was unable to locate it "down below."
 
Ok — found it! Dealer showed it to me as it is a small hose end that does hang down into easy view, but it is right where you said. Thanks a ton!

As I told the dealer, “The more I know about my bike the more I enjoy it. And I have often found myself living a LONG way from a dealer, so knowing this stuff is always handy, and occasionally necessary.”
 
BINGO!

That's the one.

Probably the easiest way to describe how to find it is: It's directly behind the oil filter, centerline of the bike. I was able to feel for it on Alcina, hands-only.

Mike
 
LarryZ said:
It probably easiest to find relative to the lambda probe in the left muffler (assuming they are still called that).

I took a pic on a brand new Rocktane at a dealership; the drain plug is the plastic insert in the end of the hose circled in red below.


View attachment 11717
Click to expand...
Fantastic! ... thanks for the pic! that helps a bunch !!
 
I was just looking at this yesterday because apparently I enjoy suffering. What a generous hose length they decided on. Who needs to actually reach anything? Silly me, thinking I could hold the hose AND remove the plug. So I’ve resigned myself to waiting on surgical forceps from Amazon, because that’s just a totally normal thing to need for this. On the bright side, at least when I’m done I can use them to hold a J, so there is some upside.
 
fleabag said:
I was just looking at this yesterday because apparently I enjoy suffering. What a generous hose length they decided on. Who needs to actually reach anything? Silly me, thinking I could hold the hose AND remove the plug. So I’ve resigned myself to waiting on surgical forceps from Amazon, because that’s just a totally normal thing to need for this. On the bright side, at least when I’m done I can use them to hold a J, so there is some upside.
Click to expand...
You are supposed to drain this after every ride!
 
Ulrich said:
I agree ... i have 22 000 miles on the bike and have never drained that even once ...
Click to expand...
I’m doing it because it’s listed in the maintenance schedule. I fully expect to see nothing there.
 
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