Oil spots on air filter

-->> T.G. Lambach <<-- wrote:
> Oil is blowing into the air filter from the crankcase breather tube
> that's attached to the motor's valve cover. Either the motor is showing
> signs of wear - piston rings allowing blow-by or, if it has a vacuum
> pump, a leak somewhere in the car's vacuum system is dumping air into
> the motor (vacuum pump exhausts into the motor in many cases) that air
> then needs to be expelled - into the air cleaner.
>
> If the motor has done > 250,000 miles the rings become quite suspect
> except if you KNOW there's a vacuum leak(s) in the car.

Thank you T.G.L.

The car has a mere 90,200 miles on it
 >> Stay informed about: Oil spots on air filter 

-->> T.G. Lambach <<-- wrote:
> Oil is blowing into the air filter from the crankcase breather tube
> that's attached to the motor's valve cover. Either the motor is showing
> signs of wear - piston rings allowing blow-by or, if it has a vacuum
> pump, a leak somewhere in the car's vacuum system is dumping air into
> the motor (vacuum pump exhausts into the motor in many cases) that air
> then needs to be expelled - into the air cleaner.
>
> If the motor has done > 250,000 miles the rings become quite suspect
> except if you KNOW there's a vacuum leak(s) in the car.


Thank you T.G.L.

The car has a mere 90,200 miles on it and the oil
has been checked and
changed regularly, so there should be little wear.
I'll have to look for that
vacuum pump and its lines. At one point a few
years ago I did have to
change a small plastic piece that was supposed to
be part of a vacuum system.
 >> Stay informed about: Oil spots on air filter 

RF wrote:
> -->> T.G. Lambach <<-- wrote:
>> Oil is blowing into the air filter from the crankcase breather tube
>> that's attached to the motor's valve cover. Either the motor is
>> showing signs of wear - piston rings allowing blow-by or, if it has a
>> vacuum pump, a leak somewhere in the car's vacuum system is dumping
>> air into the motor (vacuum pump exhausts into the motor in many cases)
>> that air then needs to be expelled - into the air cleaner.
>>
>> If the motor has done > 250,000 miles the rings become quite suspect
>> except if you KNOW there's a vacuum leak(s) in the car.
>
>
> Thank you T.G.L.
>
> The car has a mere 90,200 miles on it and the oil has been checked and
> changed regularly, so there should be little wear. I'll have to look for
> that
> vacuum pump and its lines. At one point a few years ago I did have to
> change a small plastic piece that was supposed to be part of a vacuum
> system.

The part I replaced was the Vacuum Control Unit
 >> Stay informed about: Oil spots on air filter 

I can't help you on the vacuum system's details but the theory is that a
leak somewhere allows air to be pumped into the motor (via the pump) and
that excess air blows lube oil into the air filter. A Mity-Vac (or
similar name) vacuum pump can be used to find vacuum leaks.

I (eventually) found that my 617.950 engine blows oil up the air
cleaner's oil drain pipe on hard acceleration, staining the paper air
filter, whenever the oil level was too high due to careless repair shop
overfilling on an oil change.

--

© 2008 T.G.Lambach. Publication in any form requires prior written
permission.
 >> Stay informed about: Oil spots on air filter 

-->> T.G. Lambach <<-- wrote:
> I can't help you on the vacuum system's details but the theory is that a
> leak somewhere allows air to be pumped into the motor (via the pump) and
> that excess air blows lube oil into the air filter. A Mity-Vac (or
> similar name) vacuum pump can be used to find vacuum leaks.
>
> I (eventually) found that my 617.950 engine blows oil up the air
> cleaner's oil drain pipe on hard acceleration, staining the paper air
> filter, whenever the oil level was too high due to careless repair shop
> overfilling on an oil change.
>

A belated thanks TGL for the info. I have been
bogged down with other things recently and will be
looking at this problem again soon.

This is the first time I have seen lots of
discrete oil drops. The filter normally has a
uniformly sprayed look in places and moderately
clean at others.
 >> Stay informed about: Oil spots on air filter 

RF wrote:
> -->> T.G. Lambach <<-- wrote:
>> I can't help you on the vacuum system's details but the theory is that
>> a leak somewhere allows air to be pumped into the motor (via the pump)
>> and that excess air blows lube oil into the air filter. A Mity-Vac (or
>> similar name) vacuum pump can be used to find vacuum leaks.
>>
>> I (eventually) found that my 617.950 engine blows oil up the air
>> cleaner's oil drain pipe on hard acceleration, staining the paper air
>> filter, whenever the oil level was too high due to careless repair
>> shop overfilling on an oil change.
>>
>
> A belated thanks TGL for the info. I have been bogged down with other
> things recently and will be looking at this problem again soon.
>
> This is the first time I have seen lots of discrete oil drops. The
> filter normally has a
> uniformly sprayed look in places and moderately clean at others.

I finally got around to this problem in which my
'83 240D's air filter is becoming very spattered.

The oil level in the engine is about 1/4" down
from the max level. As T G Lambach (thank you TGL)
suggested, I have acquired a vacuum pump and now I
have to figure how to apply it. I lifted the cover
of the air filter and there were several large
drops of oil at the mouth of the incoming pipe
from the cylinder head cover and the filter was
more spattered than a week ago.

Most fortunately I chose a car with the least
possible complications and, as a result, I have a
very simple vacuum system. There is a single white
line about 3/8" diameter going from the vacuum
pump to brake unit. About a foot short of the
brake unit there is a T junction off the 3/8" line
which then splits into two small pipes - one light
brown and one dark brown. Both of those go through
the firewall, possibly to the steering lock.
Another light brown pipe, of the same size as that
small pair, comes back out of the firewall and
connects to the valve (a check valve?) on top of
the injection pump. I don't yet know how the three
are connected in the dash area. My 3 big fat
manuals seem to have no diagram of this vac
system. They do have several for the later EGR
system. I believe there are line diagrams in the
manuals for the vacuum but I couldn't find it.
Looking for something in those manuals is like
going down a great black hole.

I propose to pull the two small pipes off the T,
plug the hole with a golf tee, and then measure
the pump pressure.

Then I guess I could apply the pump to the two
light+dark tubes and see if the car key position
makes a difference.

Finally, and this one has me stumped, the
connection to the injection pump. Is the function
of this to lower the pressure in the pump so that
the suction speeds the fuel into the pump, and to
provide a check valve to keep the fuel from
getting onto the vacuum lines?

TIA
 >> Stay informed about: Oil spots on air filter 

On Jul 13, 1:54 am, RF <R....DeleteThis@NoDen.con> wrote:
> RF wrote:
> > -->> T.G. Lambach <<-- wrote:
> >> I can't help you on the vacuum system's details but the theory is that
> >> a leak somewhere allows air to be pumped into the motor (via the pump)
> >> and that excess air blows lube oil into the air filter. A Mity-Vac (or
> >> similar name) vacuum pump can be used to find vacuum leaks.
>
> >> I (eventually) found that my 617.950 engine blows oil up the air
> >> cleaner's oil drain pipe on hard acceleration, staining the paper air
> >> filter, whenever the oil level was too high due to careless repair
> >> shop overfilling on an oil change.
>
> > A belated thanks TGL for the info. I have been bogged down with other
> > things recently and will be looking at this problem again soon.
>
> > This is the first time I have seen lots of discrete oil drops. The
> > filter normally has a
> > uniformly sprayed look in places and moderately clean at others.
>
> I finally got around to this problem in which my
> '83 240D's air filter is becoming very spattered.
>
> The oil level in the engine is about 1/4" down
> from the max level. As T G Lambach (thank you TGL)
> suggested, I have acquired a vacuum pump and now I
> have to figure how to apply it. I lifted the cover
> of the air filter and there were several large
> drops of oil at the mouth of the incoming pipe
> from the cylinder head cover and the filter was
> more spattered than a week ago.
>
> Most fortunately I chose a car with the least
> possible complications and, as a result, I have a
> very simple vacuum system. There is a single white
> line about 3/8" diameter going from the vacuum
> pump to brake unit. About a foot short of the
> brake unit there is a T junction off the 3/8" line
> which then splits into two small pipes - one light
> brown and one dark brown. Both of those go through
> the firewall, possibly to the steering lock.
> Another light brown pipe, of the same size as that
> small pair, comes back out of the firewall and
> connects to the valve (a check valve?) on top of
> the injection pump. I don't yet know how the three
> are connected in the dash area. My 3 big fat
> manuals seem to have no diagram of this vac
> system. They do have several for the later EGR
> system. I believe there are line diagrams in the
> manuals for the vacuum but I couldn't find it.
> Looking for something in those manuals is like
> going down a great black hole.
>
> I propose to pull the two small pipes off the T,
> plug the hole with a golf tee, and then measure
> the pump pressure.
>
> Then I guess I could apply the pump to the two
> light+dark tubes and see if the car key  position
> makes a difference.
>
> Finally, and this one has me stumped, the
> connection to the injection pump. Is the function
> of this to lower the pressure in the pump so that
> the suction speeds the fuel into the pump, and to
> provide a check valve to keep the fuel from
> getting onto the vacuum lines?
>
> TIA- Hide quoted text -
>
> - Show quoted text -


The vac line to the injection pump activates a bellows that shuts of
the fuel flow and hence stops the engine. It's activated from a vac
valve on the ignition switch. If that line develops leaks, the car
will start to take longer to stop when the key is turned off. If it
leaks real bad, the car will not stop at all.

I'd check where the vac lines go through the firewall. On my 300SD I
had two fail right at that point. Not sure why, it wasn't a sharp
bend or anything. Could be vibration perhaps. When trying to find
the leak, I just wiggled them a bit and the bad one broke right off.
 >> Stay informed about: Oil spots on air filter 

The task is to determine IF there's a vacuum leak - somewhere in the
car. The engine's vacuum pump provides the vacuum for the power brake,
the engine's controls and the "comfort system" (door locks & climate
control). That comfort system is the prime suspect for a vacuum leak, IMHO.

My '80 300SD has two vacuum connections to its vacuum pump: the large
one for the power brake etc and a small line for its "comfort system".
IMHO you need to find the source connection for your car's comfort
system and put the tester onto that line. If there's a leak then the
door locks are the next suspect to be checked.

My 300SD has a white vacuum control valve on the top rear of its
injection pump; its function is to regulate the vacuum to the automatic
transmission's shift modulator based on the throttle's position; your
240D may be the same. Don't touch this valve, its not adjustable and
quite expensive to replace if damaged.

The engine shut down device is located on the aft end of the injection
pump, facing the oil filter; it has one vacuum line attached, it's
probably dark brown.

Hope this helps you.
--

© 2008 T.G.Lambach. Publication in any form requires prior written
permission.
 >> Stay informed about: Oil spots on air filter 

trader4 DeleteThis @optonline.net wrote:
> On Jul 13, 1:54 am, RF <R... DeleteThis @NoDen.con> wrote:
>> RF wrote:
>>> -->> T.G. Lambach <<-- wrote:
>>>> I can't help you on the vacuum system's details but the theory is that
>>>> a leak somewhere allows air to be pumped into the motor (via the pump)
>>>> and that excess air blows lube oil into the air filter. A Mity-Vac (or
>>>> similar name) vacuum pump can be used to find vacuum leaks.
>>>> I (eventually) found that my 617.950 engine blows oil up the air
>>>> cleaner's oil drain pipe on hard acceleration, staining the paper air
>>>> filter, whenever the oil level was too high due to careless repair
>>>> shop overfilling on an oil change.
>>> A belated thanks TGL for the info. I have been bogged down with other
>>> things recently and will be looking at this problem again soon.
>>> This is the first time I have seen lots of discrete oil drops. The
>>> filter normally has a
>>> uniformly sprayed look in places and moderately clean at others.
>> I finally got around to this problem in which my
>> '83 240D's air filter is becoming very spattered.
>>
>> The oil level in the engine is about 1/4" down
>> from the max level. As T G Lambach (thank you TGL)
>> suggested, I have acquired a vacuum pump and now I
>> have to figure how to apply it. I lifted the cover
>> of the air filter and there were several large
>> drops of oil at the mouth of the incoming pipe
>> from the cylinder head cover and the filter was
>> more spattered than a week ago.
>>
>> Most fortunately I chose a car with the least
>> possible complications and, as a result, I have a
>> very simple vacuum system. There is a single white
>> line about 3/8" diameter going from the vacuum
>> pump to brake unit. About a foot short of the
>> brake unit there is a T junction off the 3/8" line
>> which then splits into two small pipes - one light
>> brown and one dark brown. Both of those go through
>> the firewall, possibly to the steering lock.
>> Another light brown pipe, of the same size as that
>> small pair, comes back out of the firewall and
>> connects to the valve (a check valve?) on top of
>> the injection pump. I don't yet know how the three
>> are connected in the dash area. My 3 big fat
>> manuals seem to have no diagram of this vac
>> system. They do have several for the later EGR
>> system. I believe there are line diagrams in the
>> manuals for the vacuum but I couldn't find it.
>> Looking for something in those manuals is like
>> going down a great black hole.
>>
>> I propose to pull the two small pipes off the T,
>> plug the hole with a golf tee, and then measure
>> the pump pressure.
>>
>> Then I guess I could apply the pump to the two
>> light+dark tubes and see if the car key position
>> makes a difference.
>>
>> Finally, and this one has me stumped, the
>> connection to the injection pump. Is the function
>> of this to lower the pressure in the pump so that
>> the suction speeds the fuel into the pump, and to
>> provide a check valve to keep the fuel from
>> getting onto the vacuum lines?
>>
>> TIA- Hide quoted text -
>>
>> - Show quoted text -
>
>
> The vac line to the injection pump activates a bellows that shuts of
> the fuel flow and hence stops the engine. It's activated from a vac
> valve on the ignition switch. If that line develops leaks, the car
> will start to take longer to stop when the key is turned off. If it
> leaks real bad, the car will not stop at all.
>
> I'd check where the vac lines go through the firewall. On my 300SD I
> had two fail right at that point. Not sure why, it wasn't a sharp
> bend or anything. Could be vibration perhaps. When trying to find
> the leak, I just wiggled them a bit and the bad one broke right off.
>

Thank you Trader4 for the info.

I traced the lines I mentioned in the last post
and found that the dark brown tube is redundant
and plugged. One of the light brown lines goes
from the T on the 3/8" line to the steering lock
and then back to the injection pump - the return
leg has a faint bluish stripe in it. The tubes
pass through a rubber grommet in the firewall and
they are well protected there. They look almost
like new.

Yesterday I tried to start the car, after a week
of being idle, and it was slow to start, so I bled
a litttle more air from the fuel line. In the
previous week I replaced a gasket between the
injection pump and the engine block, so I had to
take out the pump and all the fuel lines around
it. Yesterday after it started I drove around the
block. Finally I turned off the ignition and the
engine stopped immediately, so I guess the vac
line to the pump is working ok. It seems to me
that this doesn't solve the problem of the
spatters on the air filter.

Tomorrow I will start the engine and check the
vacuum level in the 3/8" line with it attached to
the brake unit and with it disconnected. I don't
like the noise the engine makes in this quiet
neighborhood and tomorrow, Monday, is a better day.

Have a great week
 >> Stay informed about: Oil spots on air filter 

Thank you TG for your effort.

-->> T.G. Lambach <<-- wrote:
> The task is to determine IF there's a vacuum leak - somewhere in the
> car. The engine's vacuum pump provides the vacuum for the power brake,
> the engine's controls and the "comfort system" (door locks & climate
> control). That comfort system is the prime suspect for a vacuum leak, IMHO.

We are agreed on the task ahead. The car was
deliberately "designed" by me and ordered about 6
months in advance. There is NO "comfort" system.
I am a mechanical engineer and am a great believer
in simplicity. I intended to live near the west
coast and again deliberately avoided A.C. Any
forays inland are restricted to the cooler times
of the year.

> My '80 300SD has two vacuum connections to its vacuum pump: the large
> one for the power brake etc and a small line for its "comfort system".
> IMHO you need to find the source connection for your car's comfort
> system and put the tester onto that line. If there's a leak then the
> door locks are the next suspect to be checked.

The large and small connections are the same as on
mine, except that the small connection goes to the
steering lock only. There is no vacuum lock system
on mine.

> My 300SD has a white vacuum control valve on the top rear of its
> injection pump; its function is to regulate the vacuum to the automatic
> transmission's shift modulator based on the throttle's position; your
> 240D may be the same. Don't touch this valve, its not adjustable and
> quite expensive to replace if damaged.

Again I have NO auto transmission. I was acutely
aware that the mechanical
gearbox requires almost no maintenance in stark
contrast to the auto transmission and requires
less juice. Besides all that, having to change
gears while driving, helps to keep me from falling
asleep

> The engine shut down device is located on the aft end of the injection
> pump, facing the oil filter; it has one vacuum line attached, it's
> probably dark brown.

I know about that unit now - the injection pump is
the M / RSF type. The device is 1.5"
diameter x about 3/4" deep, located on top of the
pump - just behind the rear injector - and the
center is about 4" from the rear of the injection
pump. On mine the line is light brown color.

> Hope this helps you.

It does help. Thanks.
 >> Stay informed about: Oil spots on air filter 

So you have a real "simplex," a manual shift 240D. In that case the only
vacuum leak possibilities are the brake booster and vacuum reservoir.
Either of those, however, would have a massive vacuum leak that would
manifest itself in a very "hard" brake pedal for lack of power boost.

Back to the original question of oil spots from blow-by; how many miles
on this engine?
--

© 2008 T.G.Lambach. Publication in any form requires prior written
permission.
 >> Stay informed about: Oil spots on air filter 

Thanks TGL.

-->> T.G. Lambach <<-- wrote:
> So you have a real "simplex," a manual shift 240D.

Yup!

> In that case the only vacuum leak possibilities are the brake booster and vacuum reservoir.

It seems like there is no leak. I attached the
vacuum pump to a redundant line inside the car
that branched off from the main line from pump to
brake booster and, with the engine running of
course, the vacuum was 23".

> Either of those, however, would have a massive vacuum leak that would
> manifest itself in a very "hard" brake pedal for lack of power boost.

I drove the car recently after replacing the
gasket between the engine block and the
injection pump and the brakes were quite normal.
They are now too. In case my air filter was too
plugged up, I replaced it with a new one but it
was no help.

> Back to the original question of oil spots from blow-by; how many miles
> on this engine?

90,280

While the engine was running I noticed much more
smoke than usual from the exhaust and it seemed
that the engine was noisier than usual. I had to
make a few attempts to start it. Normally, at
least 90% of the time it runs on the first attempt

This is getting deeper and deeper and I am
clinging onto the brim
 >> Stay informed about: Oil spots on air filter 

When you reinstalled the injection pump how did you time the injection?

The reason I ask is the engine noise that you mention and the smoky
exhaust. I suspect the injection timing is too early (advanced) which
would account for the noise, hard starting and possibly the smoke.


Did you align the intentionally missing tooth of the injection pump's
gear with the mark cut into the flange in the pump?

Remember those slots in the injection pump's mounting flange? They allow
the pump to be turned - moving its top toward the motor advances the
timing, away retards the timing. It doesn't have to be perfect but ought
to be close.

If you didn't time it there are various "how to" posts on the internet
that you can review.

--

© 2008 T.G.Lambach. Publication in any form requires prior written
permission.
 >> Stay informed about: Oil spots on air filter