Oil leak

[ed may]

Well when it rains it pours.  Now I've discovered an oil leak.   Looks like engine oil.  Bottom of engine is damp with some grime builup and a few drips.  Looks like it's coming from between the engine and trans.  Of course my laptop won't read the repair manual dvd to even get an idea of what it could be..🙄

[dirtrider]

17 hours ago, ed may said:

Well when it rains it pours.  Now I've discovered an oil leak.   Looks like engine oil.  Bottom of engine is damp with some grime builup and a few drips.  Looks like it's coming from between the engine and trans.  Of course my laptop won't read the repair manual dvd to even get an idea of what it could be..🙄

 

Afternoon Ed 

 

What year & model are you working with (we need to know what you are working on to specifically help you).

 

It looks to be a 1200 so we will go with that but early or late 1200 can make a difference. 

 

The usual place for oil leaks on the 1200 (at the trans to engine area) is balancer shaft rear seal seeping. The early 1200 engines are worse than the later ones as BMW updated the balancer/accessory shaft to decrease oil leakage on the later 1200 engines.

 

If you are using synthetic engine oil you might try switching to a 20w50 conventional oil as I have seen that slow or stop rear balancer shaft seepage on some engines.  

 

Next time that you have the R/H side plastic's removed you might remove the air filter to see in there is a lot of oil in the bottom of the air-box.   

 

Are you sure it is engine oil???? If it is (or could be) transmission gear oil then there is a trans vent just above that area. If the transmission was overfilled it could be spitting gear oil out of the trans vent then running down.  

[dduelin]

I had a 2007 RT that lunched the transmission input shaft bearing and the seal of the bearing began leaking. Transmission oil has a distinct sulphur smell very different from engine oil smell. The picture reminds me of the golden honey look of transmission oil. Engine oil only looks that clear and clean soon after changing it. I did the work to remove and replace the transmission and the clutch which was oiled with transmission oil. I found the bad bearing problem and sourced a good used transmission. Doing the labor myself I kept the repair cost to about $850.

[lkraus]

I think this is an '06 RT?  Is that 15 years of oil leakage or just a month or two? Oil puddles on the floor? Whether you fix it yourself or have it done, the first thing you need to do is clean all the old oil and dirt off the engine. That will help you pinpoint where the oil is coming from and determine just how severe the leak may be. 

[ed may]

Hi all.  It's an 06 RT. 28,480 miles.   I was planning on cleaning it down and reassessing the leak after riding this spring.   I think it's been slowly developing,  but seems to be mostly since my last oil change in March of last year.  Again,  only 800 miles ago, so the oil is still very clean in the engine.

It was mostly clean down there last Summer.  There is one or two drips on the floor. I have been using Mobil 1 15w50 synthetic.  I will change it now and use non synthetic 20w50.  I changed the trans fluid August of 2017 at 25,000.  I'm quite sure I didn't over fill it but I do see fluid in the bottom of the airbox with some small puddling.  It looks slightly red compared to the oil on the engine.   I used Redline 75/140 non limited slip fluid.  I don't have the bottle handy right now,  but I vaguely remember it being redish.  I will check if I have the bottle at my shop later today to check.  I'll clean out the airbox too, not sure how long that fluid has been in there.  Hopefully both of these leaks will not re appear,  or if they do, hopefully it will be a lot less and can live with it.  I have to do the throttle cams first before I ride this year,  Tupperware is still off, waiting for parts and riad salts/snow to get washed away.  Thanks for the tips.  Just curious,  dirtrider,  if it turns out that the rear balance shaft seal, I'm imagining it's a big job,  remove trans and maybe clutch??  Would that be a dealer recommended repair?

 

[ed may]

Here is another sample of the oils leaking.   The oil in the airbox is on the top, round sample.  Also,  dirtrider,  I'm not sure,  but it seems unlikely that the oil in the airbox could leak down onto the engine areas where I'm seeing the leak.

[dirtrider]

3 minutes ago, ed may said:

Hi all.  It's an 06 RT. 28,480 miles.   I was planning on cleaning it down and reassessing the leak after riding this spring.   I think it's been slowly developing,  but seems to be mostly since my last oil change in March of last year.  Again,  only 800 miles ago, so the oil is still very clean in the engine.

It was mostly clean down there last Summer.  There is one or two drips on the floor. I have been using Mobil 1 15w50 synthetic.  I will change it now and use non synthetic 20w50.  I changed the trans fluid August of 2017 at 25,000.  I'm quite sure I didn't over fill it but I do see fluid in the bottom of the airbox with some small puddling.  It looks slightly red compared to the oil on the engine.   I used Redline 75/140 non limited slip fluid.  I don't have the bottle handy right now,  but I vaguely remember it being redish.  I will check if I have the bottle at my shop later today to check.  I'll clean out the airbox too, not sure how long that fluid has been in there.  Hopefully both of these leaks will not re appear,  or if they do, hopefully it will be a lot less and can live with it.  I have to do the throttle cams first before I ride this year,  Tupperware is still off, waiting for parts and riad salts/snow to get washed away.  Thanks for the tips.  Just curious,  dirtrider,  if it turns out that the rear balance shaft seal, I'm imagining it's a big job,  remove trans and maybe clutch??  Would that be a dealer recommended repair?

 

Morning Ed

 

Your transmission fluid can't get into the air box so the oil in the air box is engine oil.

 

If it is you rear balancer shaft seal leaking then changing to conventional oil could help that problem. 

 

If the motorcycle has been sitting/stored  that tends to make the balancer shaft seal more easily seep so that seep could go away after regular riding again. 

[dirtrider]

8 minutes ago, ed may said:

Also,  dirtrider,  I'm not sure,  but it seems unlikely that the oil in the airbox could leak down onto the engine areas where I'm seeing the leak.

 

Morning Ed

 

No, it can't easily get out if the air box but that means that oil is going out through the vent system. There could be a seep at the crankcase vent hose to the lower air box fitting or possibly a small pin hole (or even smaller) in the lower air box plastic housing. 

 

Clean the air box out then see if the seep goes away. 

 

My money is on the rear balancer shaft seal slightly seeping when parked.  The updated balancer shaft  (compensating shaft) parts didn't go into production until the beginning of the 2008 model. 

[ed may]

Oh, I misunderstood you,  I thought you meant the trans vent was in the airbox.  Ok, well then how is the engine oil getting into the airbox?  (Glad to hear that winter storage could increase this seepage)  I had a feeling because I don't remember it being so damp down there at the end of the riding season last year. 

[dirtrider]

5 minutes ago, ed may said:

Oh, I misunderstood you,  I thought you meant the trans vent was in the airbox.  Ok, well then how is the engine oil getting into the airbox?  (Glad to hear that winter storage could increase this seepage)  I had a feeling because I don't remember it being so damp down there at the end of the riding season last year. 

Morning Ed

 

I have seen a number of 1200 engines seep a little oil out of the balancer shaft seal while stored  (especially if the motorcycle goes through a number of temperature swings).

 

The engine vents through an impeller type vent system on the rear of the left hand cylinder head, then out through a vent hose to the bottom of the air box. 

[ed may]

Ok, we're responding to each other at the same time,  sorry for any confusion,  I'm typing replies while you are too.  So the engine breather goes into the airbox?  That makes sense,  same as car engines.  I've seen a lot of pvc systems dump oil in airboxes in cars.  If engine oil is in the airbox, does that indicate a problem?

Again, I will clean everything down,  change oil, change throttle cams,  rear caliper banjo/bleeder and hopefully be riding in a month to report back on everything. 

[ed may]

I have a good feeling the thicker non synthetic oil will help a great deal with all this.  Thanks a bunch dirtrider,  as usual you are the man.  A true Guru.  Hopefully I won't have to hit you up too much with the throttle cams job.  I'm totally capable, and I understand most of your descriptions and tips on that subject,  so we'll see.  I will certainly report back on everything. 

[dirtrider]

1 hour ago, ed may said:

So the engine breather goes into the airbox?  That makes sense,  same as car engines.  I've seen a lot of pvc systems dump oil in airboxes in cars.  If engine oil is in the airbox, does that indicate a problem?

Again, I will clean everything down,  change oil, change throttle cams,  rear caliper banjo/bleeder and hopefully be riding in a month to report back on everything. 

Afternoon Ed

 

It doesn't necessarily indicate a problem, a little oil in the air box is somewhat normal but  a lot of oil is never a good sign. 

 

If the motorcycle is ever tipped over on the L/H side with the engine running that can send slug of oil into the air box.

 

The L/H cam has a spinning impeller at the vent outlet that sort of flings the oil out of the vented crankcase air. It works pretty good as the boxer engine has serious crankcase pressure pulses due to the pistons moving in & out together. 

 

Clean the air box out, then go to 20w50 conventional oil, filling only to center of sight glass (not top of sight glass).

 

My guess is that your oil seepage will not be a problem until you park that motorcycle for a number of weeks, or more, in a temperature changing environment. 

 

 

[ed may]

All sounds good,  very interesting info.   FYI, my engine oil is at the top of the sight glass, so maybe that has something to do with it too, never heard of that tidbit of info.  The bike has never been on its side running.   It did tip over on me once years ago because I lost my balance, but picked it up right away.   As far as some oil in the airbox,  I agree, a little is acceptable considering the vent system,  especially if I never cleaned it out since I bought the bike with 2k miles on it.  So what brand of oil should I use?  😂  only kidding,.... partially. 

[ed may]

By the way,  I did get the laptop to read the repair manual dvd.  Not sure if it's going to work,  but I'm trying to copy the files to my laptop in case I ever lose the dvd, it gets damaged,  or whatever.   Not sure how it's going to turn out, hopefully,  if it copies, the files will stay in order and be easy to navigate.   Anywho,  replacing that counter shaft seal looks like a pretty big job with some special tools involved.   It's the one right above that small dime sized freeze out type of plug, right?  Looks like the balance shaft is splined to a shaft in the block and it just slides off to replace the seal?  Would have to borrow an engine crane from a friend for sure. Hopefully I won't be going down that road....

[dirtrider]

26 minutes ago, ed may said:

By the way,  I did get the laptop to read the repair manual dvd.  Not sure if it's going to work,  but I'm trying to copy the files to my laptop in case I ever lose the dvd, it gets damaged,  or whatever.   Not sure how it's going to turn out, hopefully,  if it copies, the files will stay in order and be easy to navigate.   Anywho,  replacing that counter shaft seal looks like a pretty big job with some special tools involved.   It's the one right above that small dime sized freeze out type of plug, right?  Looks like the balance shaft is splined to a shaft in the block and it just slides off to replace the seal?  Would have to borrow an engine crane from a friend for sure. Hopefully I won't be going down that road....

Afternoon Ed

 

Putting that BMW DVD on your laptop might or might not work.  There is an anti-copy something or other in that DVD that doesn't seem to allow some DVD readers to copy over a usable copy.  I have my BMW repair DVD's on my laptop but had to use an old win 98 computer with very old DVD reader to get then transferred to work correctly.   

 

On the rear balance shaft seal, yes it is on lower rear of engine behind flywheel so trans has to be removed but engine can stay in motorcycle. 

[BMWED]

I use conventional 20w50 and put in half a quart of high milage oil. It has seal conditioners in it that keep the seals soft. The conditioner also swells the seals a bit, I believe.

[ed may]

Follow up, I cleaned it down, and put Castrol "GO" 20W50 4T conventional  motorcycle oil in it and went 100 miles today.  It's still clean.

 

[dirtrider]

On 3/13/2021 at 7:21 PM, ed may said:

Follow up, I cleaned it down, and put Castrol "GO" 20W50 4T conventional  motorcycle oil in it and went 100 miles today.  It's still clean.

 

Morning Ed

 

That is pretty typical of the BMW 1200 engine rear seal oil seep. They don't seem to seep while riding, my guess is that you won't see any signs of a rear balance shaft seal seep until you park the motorcycle for a few weeks without use.