TheSamba.com :: View topic - Perplexed! Clogged Breather > Mainseal Leak > FIXED???

Mon Oct 30, 2023 2:25 pm

“Perplexed” barely covers this one...

We’re now on the return trip back west after going from Bayfield, Colorado, to the SCCA Runoffs in Virginia (sports car national championships), down Blue Ridge into Georgia, Alabama, Mississippi, Arkansas, Louisiana, and into eastern Texas now.

I’ve bragged hereabouts that we lost no oil over the first 3,000+ miles, running at about 0.1 above the low notch on the dipstick, then we showed about 0.2 of the stick loss over the next thousand, and attributed that to not having a new drain plug washer that did show a very small leak spot about 3,000 miles ago — and oil level anomalies that sometimes occur.

Then I swapped in a new oil filter maybe 700 miles ago, and drove about 300 miles. In a cursory engine bay check, I found a sizable oil puddle just below the access port at the driver’s forward part of the engine, and started with real concern.

I cleaned it up, oil level was at maybe 0.3 between the notches, and drove about 250 miles to a new campsite. There, the puddle was back and concerns were reaching freakout proportions, as some friends here can attest. Know that roughly 25% of the past five years have had us off the road and we all have limits!

So I pulled off the crankcase breather on a hunch, as supported by a concerned air-cooled mechanic in Las Cruces I called to try to convince doing a mainseal if we were able to limp like a thousand miles to get there. Michael lists himself as “Vintage Air Cooled German Cars” online, and spent a long while of dedicated interest on a non-customer out of a genuine VW brotherhood that has definitely waned over our decade of ownership, suggesting shops from Little Rock to Tucson, and even contacting a couple. THANKS MICHAEL!!!

So in pulling off the aftermarket breather everyone carries now for lack of an original VW one, it was clearly clogged with oily dirt closing off the tiny hole under the lip. There *was not* a hole when purchased, so I drilled one to match what VW did... but luckily kept my old original tower as a spare.

I soaked both towers a bit too long yesterday, using carb cleaner out of sheer ignorance when I had a feeling I should have used my mineral spirits. Having little experience with carb cleaner and its effect on rubber it was a BIG MISTAKE, or maybe not... the solvent destroyed the diaphragms on both, though to be fair I didn’t study them before cleaning. But what I do know is sucking on the original no longer moved the diaphragm, and it absolutely *was moving* before the soaking.

Before we left today, the stick was at 0.3. We drove about 100 miles, and the stick showed the oil level with the top notch, when I’d predicted about 0.0 to 0.2 based on losing 0.3 on the prior 250 mile run that created the second puddle.

And suddenly there’s no leakage atop the block at all!

I may be premature and will check the level and the block all the way west. My theory is the crankcase pressure got high enough with the clogged breather as to trap oil in recesses I am unaware of, and force oil out of the path of least resistance... presumably the mainseal in this case.

I just bought a jug of ATP stop leak in case this isn’t fixed. But at this point we feel a ton of relief, whereas yesterday we felt we’d *finally had enough*.

Thanks to my friends here, you know who you are.

Mon Oct 30, 2023 2:38 pm

Glad to hear about the progress- maybe the service life of these new breather towers isn’t as long as we’d like… :(

Mon Oct 30, 2023 3:02 pm

Good to hear you may have inadvertently fixed it!

I've never been convinced of the need for a new breather tower.
Oh, to be clear mine is 100% shot and I removed the rest of the rotten rubber three years ago!

Unlike you, I siliconed (yes, I actually used silicone! 😳) that stupid tiny little hole on the rim because it blew out oil all over the engine case top!

My oil use is so little that I almost never check it any more.

Not sure that the tower is needed or does much..... who knows?
I'll continue to motor along in ignorant bliss until something happens to convince me otherwise.

Mon Oct 30, 2023 3:45 pm

here's my previous photos, tests, and musings on the breather tower, starting the link on Page 2 for the ADD folk. still don't know what the heck the design operation was supposed to be-- need those dead VW engineers to resurface.
https://www.thesamba.com/vw/forum/viewtopic.php?t=...p;start=20

here's a lonnnngggggg thread on the breather tower.
https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

i have no conclusion on this device. i don't carry a spare.

Mon Oct 30, 2023 3:48 pm

\:D/ :popcorn: :popcorn: :popcorn: :-k

Mon Oct 30, 2023 4:32 pm

The new breather towers from JP Crap have the little drain hole in the inner elbow/p-trap thing.

These towers are built in similar fashion/logic as the hockey pucks on inline engines with the membrane.

Mon Oct 30, 2023 6:36 pm

Thanks for the input, All!

Too whooped now to reply coherently, not that there’s anything new there.

Drove a few hundred miles today. Oil’s gone down from full top notch to about 0.7, which I’d consider normal loss from top notch.

We’ll see tomorrow, if engine block is still dry I will feel better. I only went 55 before seeing it dry before lunch today, since then I’ve gone 65 to 70 in case revs have any bearing on leakage from case.

Still little drip mark on ground but no more new oil on bumper or hatch, think there’s just some left at bell housing bottom.

The entire sitch is confounding. But I am reasonably convinced that when the little hole is clogged, there’s high enough crankcase pressure to cause a leak.

Or not. :lol:

Thanks for the input!

Mon Oct 30, 2023 7:23 pm

That hole was to allow atmospheric pressure on the top of the otherwise sealed rubber diaphragm.
As the diaphragm moved that hole vented the sealed top of it.

Tue Oct 31, 2023 7:11 am

jlrftype7 wrote: Glad to hear about the progress- maybe the service life of these new breather towers isn’t as long as we’d like… :(
I’m not sure whether the tower was flawed or not compared to the original. But if clogging indeed adds to case pressure, I’d call that a design flaw from conception for anyone doing any amount of dusty driving. It only has maybe 10,000 miles since last cleaning.

djkeev wrote: Good to hear you may have inadvertently fixed it!

I've never been convinced of the need for a new breather tower.
Oh, to be clear mine is 100% shot and I removed the rest of the rotten rubber three years ago!

Unlike you, I siliconed (yes, I actually used silicone! 😳) that stupid tiny little hole on the rim because it blew out oil all over the engine case top!

My oil use is so little that I almost never check it any more.

Not sure that the tower is needed or does much..... who knows?
I'll continue to motor along in ignorant bliss until something happens to convince me otherwise.

djkeev wrote: That hole was to allow atmospheric pressure on the top of the otherwise sealed rubber diaphragm.
As the diaphragm moved that hole vented the sealed top of it.

“Who knows?” indeed.

I suspect if yours hadn’t blown oil all over, you may have experienced exactly what I have... a leak. The pressure has to go somewhere if excessive, leaving the questions of when and why pressures are too high. I also suspect excessive oil may well be a factor in excessive pressure.

DanHoug wrote: here's my previous photos, tests, and musings on the breather tower, starting the link on Page 2 for the ADD folk. still don't know what the heck the design operation was supposed to be-- need those dead VW engineers to resurface.
https://www.thesamba.com/vw/forum/viewtopic.php?t=...p;start=20

here's a lonnnngggggg thread on the breather tower.
https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

i have no conclusion on this device. i don't carry a spare.

Your findings are very curious, and deepen the mystery. Thanks for posting them before, and for the link.

I read that other thread Saturday, and have before. In the end, not very definitive if not too much information.

I’m as-yet unconvinced that any posts have definitively described just what the heck the vent does, and how it does it — or that was answered and my eyes had glazed over by then. If intended to relieve excess pressure, and the little hole is the only escape, then clearly it shouldn’t be plugged up.

In other words, if the diaphragm is intended to be fully-sealed below it, why does it even exist? Or does the diaphragm rise *above* the hole when pressures increase? And if they do, wouldn’t relief only come if the hole is unplugged?

Am I missing something besides the obvious? :wink:
bobbyblack wrote: \:D/ :popcorn: :popcorn: :popcorn: :-k
Recommend parmesan. :wink:

ALIKA T3 wrote: The new breather towers from JP Crap have the little drain hole in the inner elbow/p-trap thing.

These towers are built in similar fashion/logic as the hockey pucks on inline engines with the membrane.

Both of mine have the elbow hole.

Thanks Again to All, appreciated!

Fri Nov 03, 2023 8:22 am

We made it to New Mexico, going just over 1,000 miles from Monday to Wednesday.

We left with full oil and lost *maybe* a half-stick in 1,000 miles, which I’ve found to be normal when the oil starts at the top notch.

The dipstick levels have been inconsistent, and am very curious why... it’s almost as if the oil level in the filter is ranging from full to empty... bizarre.

The oil leak out the forward engine port to the engine top immediately and completely stopped when changing the crankcase breather.

The remnant leak(s) from the engine-to-trans gasket have slowed with every viewing, and are down to one drip at gas stations. Once all that oil’s dripped out, it will soon leave no drips at all.

I never used the ATP oil stop leak.

It is dead clear to me that clogged or blocked-off breathers can cause a mainseal leak. User beware, yours may be next.

Thanks Again to all who helped!

Tue Nov 21, 2023 10:50 am

So… does anyone know how oil can possibly leak out of the access port above the bellhousing, at the forward driver’s side of the engine?

The only way I can surmise this being possible is oil leaking out the mainseal, and traveling vertically up the forward side of the engine before reaching the port… possibly from the spinning of the flywheel…

Does anyone know the specific conditions that can cause too much crankcase pressure?

Thanks for the help so far, but I’m left with more questions than answers.

Though we’re no longer getting oil atop the engine from the port, now we have a leak from the pushrod tubes, and possibly both leaks have a common connection of having too much crankcase pressure.

Tue Nov 21, 2023 11:25 am

E1 wrote: So… does anyone know how oil can possibly leak out of the access port above the bellhousing, at the forward driver’s side of the engine?

several places to leak on the front of the engine... main seal, cam plug, oil gallery plug.

you likely do have high crankcase pressure but the tower might be a red herring. pull the hose off of it and suck and blow thru the hose barb. have your partner take a picture of course. i'll bet it is totally open, which is what a brand new one does as well as one with rotted diaphragm. run the engine with the hose off and feel how much blowby is coming out of the tower barb. this is subjective but is it a crazy amount? like you could inflate an air mattress with it? or is it just a gentle breeze or even a suck/blow reflux, which is ideal.

the inline hose heater for the tower hose has a 5mm port in it to restrict air flow to reduce unmetered air. just for giggles, you could pull that heater+restriction off while it is running and see if the engine dies from too much unmetered air. it likely will. but if you have excess blow by, you could try different sized orifices above 5mm. just going from a 5mm orifice to 6mm is a 144% increase in surface area of the hole! it would scavenge more blowby and your Lambda system should be able to correct for the extra unmetered air.

all assuming you have too much blowby. which you may not.

Tue Nov 21, 2023 11:40 am

Thank You, Dan!

I do not think our Digijet setup has an inline hose heater, nor did our prior ‘84… unless I’m confused by where that is. This motor is a 2.1 fitted to all Digijet bits.

The hose from tower to intake is a good silicone one, a year old, and has absolutely no oil beyond a thin film in it — and never has had anything beyond that, either.

Compression good, definitely no piston or ring blowby, if that’s what you meant, engine runs great and beyond these leaks has never used oil — in fact, quite the opposite, happily, until a month ago.

Is it possible to have a leak somewhere that has vacuum, and it’s drawing in air that can’t escape?

Being remote, I may not work on this until getting a new tower, it’s the only element that seemed to be a cause so far. I’m mostly thinking ahead and hope to gather data to work with instead of once things are apart in the desert somewhere.

The leak from having excess oil in the bellhousing has slowed to a tiny spot under the van when parked, and only when being full-hot. I think that leak has totally stopped but there’s still a little left to slowly seep out.

Thanks as Always!