Where is the Leak?

[kmisterk]

Preface:

So uh. I made a mistake and let the bike burn the oil dry. It didn't make it home, more because I was terrified to do irreversible damage, and had my dad trailer it back to my place once the engine started making louder valve-rattle noise.

I was not a good rider and didn't properly check fluids, and my only reasoning for this was that I had figured 800 miles was too soon to start worrying about oil level. Jokes on me, now. I will be much more prudent going forward about oil checks at every tank of fuel.

Finally got some oil in it to make sure things were okay, and now it sounds like it's got some poorly adjusted valve rocker arms and it has a pretty major leak coming from somewhere *near* (maybe from directly?) the oil filter cover. I don't believe it to be the oil filter cover, as it's literally just been changed in hopes to stifle the leak, as it really does look like it came from this cover.

For complete clarity, I was not able to get ahold of the normal oil I use, the BMW 20w-50 Mineral Oil (old metal can, Alantec or some brand like that, with BMW's logo on it), and instead settled on Valvoline VR1 20w-50 racing oil, as it has some of the zinc-based additives that snowbum seems to talk about being good for the older airheads and push-rod engines, and was literally the only 20w-50 oil with zinc additives I could find locally (Even the dealership I normally get my 20w-50 mineral oil at was out of stock and didn't have any recommended alternatives in stock).

I have three questions:

1. Could the drastic change in oil be part of what's causing the leak?
2. What is leaking?
3. Does this sound like just bad valve clearance issues or does it sound like I may have a bigger problem on my hand?

Caution: IT GETS LOUD




My Thoughts

My hopes, really, but I'm thinking that 2 things likely need to happen:

A valve clearance and rocker adjustment (eliminate the rattle), and new pushrod seals. Does this sound accurate? Any other insight?

[gspd]

So you actually ran it dry, like until the oil light went on, or beyond that?
There's no way you could have gone 800 miles without noticing a leak like that or possibly crashing from an oil soaked rear tire.

Unfortunately, it really sounds like a connecting rod knock to me.
I'd pull the top end and check the con rod bearings before starting it again.

The leak is definitely from the filter housing; Improper O-ring, gasket, spacer or filter installation.
Pushrod seals can't leak that profuseIy (short of being totally absent).

FYI, In the future, don't concern yourself about things like zinc additives and all that crap.
Any brand 20w50 will work just fine for many hundreds of thousands of miles if it's changed often.
If you have absolutely no choice, temporarily use 10w40, 10w30, or even 5w30; just change it again ASAP at the very first opportunity.

Always keep in mind that ANY OIL, from 0w20 to straight 50W will always work 1000% better than NO OIL.
Even used oil scavenged from a long ago abandoned car in a farmer's field is better than no oil.
There's no way that leak is caused by 'wrong' oil.

Sorry for your bad luck.

[kmisterk]

So you actually ran it dry, like until the oil light went on, or beyond that?
There's no way you could have gone 800 miles without noticing a leak like that or possibly crashing from an oil soaked rear tire.

Ran it until the light was on solid at idle, tried another mile or so. Stopped after that cause I was nervous about the light being on at all.

Unfortunately, it really sounds like a connecting rod knock to me.
I'd pull the top end and check the con rod bearings before starting it again.

That's the plan this weekend. Any specifics we're looking for on the way to getting the top-end off?

The leak is definitely from the filter housing; Improper O-ring, gasket, spacer or filter installation.
Pushrod seals can't leak that profuseIy (short of being totally absent).

My worry here is that I had *literally* just done a filter change 10 minutes before taking this video. both rubber end-pieces of the previous filter separated from the filter and were semi-stuck to the end pieces (inside the chamber, and stuck to the cap). Not like, *melted* to them, but detached from the oil filter body, at least. It's entirely possible I didn't get the seal correct. But it was leaking similarly *before* this change, and only just noticed it after refilling it since this incident happened. I would be hard-pressed to say that I missed a leak of this severity over the last 800 miles. I just don't see that being the case. I can't completely rule it out, though.

FYI, In the future, don't concern yourself about things like zinc additives and all that crap.
Any brand 20w50 will work just fine for many hundreds of thousands of miles if it's changed often.

Kind of what I had figured, and ultimately it came down to two choices: Castrol GTX Standard 20w-50 and the Valvoline VR1.

Also keep in mind, in a pinch, ANY OIL, from 0w20 to straight 50W will always work 1000% better than NO OIL.
Even used oil scavenged from a long abandoned car in a farmer's field is better than no oil.

Sorry for your bad luck.

Noted. And thanks for the tips, as always. I'm *sincerely* hoping that this is nothing beyond "whoops" and I can get her back healthy again asap.

[gspd]

Positioning and condition of white O-ring #5 and metal washer #6 are CRITICAL.

# 4 gasket is not necessary (or even advised by me). The white O-ring renders the gasket redundant.
My bike hasn't used one since it's infancy.
I don't use it on customer bikes unless the customer insists on it after being informed.
There may or may not have been a service bulletin about this a hunnert years ago.

That white O-ring should NEVER EVER be re-used, but it's not included in the BMW filter kits.

[kmisterk]

Positioning and condition of white O-ring #5 and metal washer #6 are CRITICAL.

# 4 gasket is not necessary (or even advised by me). The white O-ring renders the gasket redundant.
My bike hasn't used one since it's infancy.
I don't use it on customer bikes unless the customer insists on it after being informed.
There may or may not have been a service bulletin about this a hunnert years ago.

That white O-ring should NEVER EVER be re-used, but it's not included in the BMW filter kits.

Noted. The bike will not be running again until after we take a good look at the internals. I've assembled a list of parts/gaskets/consumables for this weekend that I plan to pick up from my local dealer. Hoping they have the entire list, but alas, may need to order some custom. For what it's worth, the kit I get from my local dealer *does* include the replacement o-ring, as well as the spacer and the gasket. The Filter is a two-piece folding style with the rubber ends connect to it directly. It would appear I may have not done a great job closing that cover back up earlier this evening.

I've already ordered a second kit to be used in a better environment with better access and tools while we work on the heads.

I'm hoping that this goes smoothly.

[Rob Frankham]

That sounds really nasty... sorry. One thing that surprises me a little is the volume of oil leaking to the outside... Failure of the 'O' ring will usually lead to oil leaking from the filter housing back into the sump with little or no actual loss of oil to the outside (which is one of the reasons why it's so dangerous). Be very careful to examine the condition of the 'O' ring and seals, the shim the cover and the sealing faces on the crankcase. Also check that the threads for the cover bolts are sound. Whatever you do, don't 'cure' the leak by fitting a gasket. All that will ensure is that leakage goes into the sump and you will have no indication until the light comes on again...

Rob

[melville]

Probably the best write-up I've seen on the $2,000 O-Ring:

http://largiader.com/tech/filters/canister.html

My 1978 /7 takes a shim and a gasket, as the canister is very shallow compared to the outer engine case.

The last filters I bought from Hansen's came with both a shim and an o-ring. They may have specified /7 or later when ordering the filters for stock, or it may be the way they're sending them now. I had previously bought shims and o-rings separately.

[gspd]

Probably the best write-up I've seen on the $2,000 O-Ring:
http://largiader.com/tech/filters/canister.html

This (and many other) insights on measuring canister depth, etc, are full of valid points to ponder but too time consuming and complicated for most airhead enthusiasts. Verrry long winded procedure and explanation for such a simple issue. I'm sure snobum's version is even longer.

The QUICK, EASY AND FAILPROOF way to 'measure' the gap is too put everything together and be sure that when you press the cover against the engine case that the white o-ring forces it to spring back out a bit. If the cover stays perfectly flush with the case when released, add another metal shim behind the white o-ring. For the record, I've personally NEVER had to add an extra shim, in literally thousands of filter changes.
Excerpt from your Largiader link: This is just an example, narrowly targeting a specific dimension! Do your own math to suit your own situation. In practice, the O-ring works in a fairly wide range of dimensions, so it's really unnecessary to apply this level of precision. You need to compress the O-ring, but it's not rocket science.

My 1978 /7 takes a shim and a gasket, as the canister is very shallow compared to the outer engine case.

I recommend you don't use the gasket*, it can only cause problems. Deleting the gasket will just squash the white o-ring a bit more, which is a good thing.
*except on older flat cover pre white o-ring models where it is absolutely necessary.
If your filter has a center bolt holding it in, you need the gasket.

[gspd]

Failure of the 'O' ring will usually lead to oil leaking from the filter housing back into the sump with little or no actual loss of oil to the outside

That's why I don't recommend using the gasket. That way, if the o-ring does fail, there will be an evident leak to the outside.

I remember discussing this issue in depth with different BMW factory service reps and technicians and at the time they were adamant that the way the infallible BMW engineers designed it in 'der fodderland' was the only correct way to do it. I proved them wrong, more than once over the years. Hence the moniker 'Mechaniker aus der Hölle' (Mechanic from Hell)

[Tom H Ca]

Question on the O rings..

O ring #7. The filters I have been buying for my '73 R75/5 have the sorta cone shaped rubber ends on them. AFAIK, you do not use the #7 O rings with these filters???

The OP I think is using the rubber end filters? Are you using the #7 O rings as well?

Also on my R75/5 with the rubber end filters, I know there is a gasket on the cover, but I can not remember if there is a white O ring. I have not had external leaks and never had any oil pressure issues that I know of in about 10,000 miles. I would need to pull it to be sure.

FWIW: The two oil streaks makes me think the push rod tube seals.

ALSO: To be clear.....The oil light came on at idle, BUT went out above idle right????

Low and hot oil could make the light come on at idle. Meaning MAYBE there was enough oil to lube the engine?

Tom