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Old 04-08-2004, 08:45 PM
240Joe's Avatar
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Posts: 525
I'll repeat my previous comment....this thread is bizarre. However, there are several things we can learn here.

First, you should repair these cars with mercedes parts only. Modifications are very risky. If the breather tube was broken, it should have been repaired with Mercedes parts. It looks as if it almost cost an engine in this case.

Second, even 25 year veteran mechanics provide poor advice. How can he say the engine is ok but it needs a compression test because it has one cylinder not running? That's like saying you're in great health but your leg just fell off. Then he says it has no power because of "dead injectors". Come on. This guys has the troubleshooting skills of a 5 year old.

Third, old wive's tales live on. Yeap, that Rotella and 3kmiles oil changes saved the engine. Oh brother. What can I say?

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Old 04-09-2004, 01:29 AM
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my guess: your breather tube or oil seperator blocked off
creating a back pressure into the valve cover and down into
the sump forsing oil up both the dipstick and the breathing pipe
return. the breathing pipe to oil seperator lip is a loose fit, lower than the dip stick which has a a fitted seal so the oil would flow out of it and not out of the dipstick.
no runaway engine because the cylinders were overwelmed
by oil volume, not a fine mist but globs.

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Old 04-09-2004, 05:24 AM
FrankM's Avatar
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Originally posted by notlostmaybe
my guess:no runaway engine because the cylinders were overwelmed
by oil volume, not a fine mist but globs.
very possibly globs of oil.
globs would bend a rod, hence his misfire on one cylinder could be because of low compression due to a bent rod.

The compression test the 25yr veteran wants to do would tell us more.. Perhaps he has a hunch...
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Old 04-09-2004, 12:52 PM
Coming back from burnout
Join Date: Jun 1999
Location: in the Pacific Northwest
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to 240 Joe:

I like you as a person, but I dont agree with your statements.

1) Selection of Oil really does make a difference.I dont want to get into tribology and oil science, but some oils do leave a film taht lasts just a bit longer and is thicker after the oil level itself is gone. I don think this is an old wive's tail, its a new wive's tail because in the 21st century, there are more women in management than wait until they start tinkering under the hood..

2) The injector problem is unrelated to the Breather Tube mishap. It had to do with my original loss of power when I started to mess with the car to begin with. When I described my cold start problems, he queried me about my injector lifespan

3) The engine miss is also unrelated to the cold start problem.
It was there before the breather problem and its the reason why I messed with the filters (fuel).

4) I RESPECT any guy who has been doing this stuff for 20 years,
and I do believe he is correct.
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Old 04-09-2004, 12:53 PM
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Where are you STEVEBFL and Larry Bible and BENZMAC?

I notice you have been conspicuously silent
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Old 04-09-2004, 02:39 PM
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Steve and Donnie don't monitor this forum, so if you want them you'll have to post in Tech Help or contact them directly.

Larry has limited internet time available, so he doesn't post as much as he used to.

Anybody else you want to know about?
Rick Miley
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Last edited by Rick Miley; 04-09-2004 at 02:44 PM.
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Old 04-09-2004, 08:48 PM
240Joe's Avatar
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Everyone is entitled to his opinion, and I do respect yours. However, I would run away from this mechanic as fast as my diesel would allow me, even with 4 of 5 cyclinders working.

You don't seem afraid to tackle any repair job, and have done a lot of it in the past. Why use this mechanic? Do it yourself. It will be cheaper, you will learn, and you will be a lot more independent in the future.

All IMHO, of course.

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Old 04-09-2004, 09:19 PM
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Valve stem seals. Re: Internal Pressure/Fluid Dynamics of the engine..

Originally posted by Carrameow
are difficult for me to analyze.
But yes, the Mercedes pro did verify pinching the breather tube will cause oil to go out the exhaust.
Why the dipstick tube doesn't relieve the pressure I dont know, except that remember--the bottom of the dipstick tube should well be submerged in oil so it cannot be an immediate source-of-relief to a clogged breather tube.
Elevated crank case pressure will blast through the valve stem seals, and smoke a lot.
That is why PCV (Positive Crankcase Ventilation) was mandated by the US government.
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Old 02-02-2005, 10:13 PM
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Gentlemen...and ladies, should you feel forgotten.
The issue with this is the fact the engine would have gone 'runaway' with oil of this quantity
being ingested into the combustion chambers....this is NOT what happens
when a oil breather is blocked on a turbo engine.

You have to understand how turbo's work.....
someone said they have 40 psi oil pressure...not so.
There is a restrictor in the supply to the turbo bearings because the bearings are ZERO pressure bearings !
They are flooded with oil, true, but not pressure.
The oil leaves the turbo due to gravity for the most part.
this being so, any restriction will back the oil up into the turbo oil housing and pressurize the shaft bearings....
and oil will be pumped into the exducer or exhaust turbine side and be expelled out of the muffler as wet oil and clouds of smoke.

Most turbo's will past some oil into the intake side and a little oil will enter the motor this way.
On a gas engine, the plugs foul out. On a diesel, the idle is lazy coming down and there is
sometimes detonation from the ingested oil firing off before normal injection angle.

Some oil will be pushed out of the breather, but you will hear detonation when it gets past a dribble.
During crankcase pressurizing, there will be no oil going down the valve guides, this only happens
when there is a pressure differential between the crankcase and intake air where the intake air is lower that the crankcase pressure.

Most crankcase pressure is a result of turbo pressurized intake air getting back out by way of the intake stem seals.
When the rings come under load they seal much better and blow by is reduced past them.

So to recap.....the oil was BLOWN out directly into the exhaust through the turbo shaft seals due to high crankcase pressure.
This happens because the exducer end of the shaft is very hot and thins the oil increasing the drain.
The inlet side is a lot cooler and passes much less oil.

Make sense to you ?

BTW...bin doin' this mechiniking stuff fer 45 years....
[ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

Last edited by dkveuro; 02-02-2005 at 10:19 PM. Reason: just though o' summat !
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Old 02-02-2005, 10:45 PM
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Wow.....very interesting thread. Is it alright if I say I'm glad I don't have a turbo???
Bill Reimels
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Old 02-03-2005, 02:54 AM
Posts: n/a
I vote for dkveuro's idea...

Originally Posted by kerry edwards
I hate to be the bearer of bad news, but if it's knocking, I doubt it is a matter of timing. With the lack of oil, it is likely to be the bearings that are knocking. It would only take a few minutes of driving with 0 oil pressure to cause that damage.
I disagree to some degree..

I ran my MB almost 5-6 miles at highway speeds without noticing the oil pressure dropping away after an oil line got taken out and my oil was added to my engine compartment.

Assuming he doesn't use water as oil, there will be some oil remaining and lubricating even after pressure has dropped (even though not nominal). My engine is knockless even though I didn't catch the oil loss immidately..and I had ZERO pressure.

I was running Delo 400..almost brand new..

What kind of oil were you running

Last edited by Brandon314159; 02-03-2005 at 02:59 AM.
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Old 02-03-2005, 06:12 AM
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I vote for dkveuro's idea...

Me Too.
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