Periodically Vomitting Oil - PeachParts Mercedes-Benz Forum

Bill()C · #1 08-17-2008, 10:59 AM

This one has me semi stumped that I might take it in to be serviced.

I ignored this problem for a while because I've had grounding issues with my instrument panel and found certain things unreliable (oil pressure, GP light, Lamp out light)

I have installed an aftermarket oil pressure gauge.

Periodically my low oil indicator light comes on. I checked often and had plenty of oil in the engine so I figured it was a problem with the gauge pod.

The other week I had an explosion of oil onto the top of my engine which I believe came from the oil filler tube.

I do not lose oil pressure during this unauthorized engine activity, until presumably so much oil has been blown out that I have little left. I had not noticed oil on top of the engine even during previous indicator light warnings.

I've been brave enough to test drive it around town while still trying to figure this out and for a week it was good and last night I got the indicator light and some oil blowing out again. There is no pressure / vacuum from the oil filler tube or oil cap during normal running. I haven't been able to check while the indicator light is on.

My only thoughts have to do with the vacuum pump. I do have vacuum on the line. But I don't know if it drops out when this malfunction happens. Should I hook up a test gauge while driving?

Where do you think I should start? I don't think I've lost compression in any cylinders because this is only a periodic problem. However I have not tested compression recently.

TIA,
Bill

jt20 · #2 08-17-2008, 11:13 AM

no new oil leaks? stumbling? missing? Does it only occurr when the oil is at full temp?

kerry · #3 08-17-2008, 12:10 PM

Over the years I've seen three or four reports on here describing similar events. I think the hypothesis has been a plugged crankcase ventilation system. But, I can't see how increased pressure in the crankcase will throw the oil out the filler tube. I can see how it would blow out the dipstick. Perhaps there is more oil being flung around inside the crankcase than I imagine and it simply finds its way out once the dipstick is loose.
So, I would check your vent hose from valve cover to air cleaner to make sure it is not plugged.
But what we really need are some creative minds to put their thinking caps on and try to figure out these strange events.

Bill()C · #4 08-17-2008, 01:16 PM

There is some stumbling... there has always been more stumbling, but recently I replaced two injectors just to see if it would help with the stumbling... which it did greatly. I plan on replacing the rest of the injectors after I solve this problem.

I'm going to say that yes, it does seem to happen when the engine, hence the oil, is warm. But I don't want to mislead anyone into thinking that I know this is the case for sure.

I don't have any new oil leaks... just the same old one by the IP. Which is no where near the new oil vomitting spectacular.

I'm not going to be able to check the vent hose until later today, but I will report back.

Thanks,
Bill

jt20 · #5 08-17-2008, 05:13 PM

There are rubber seals on the dipstick that detoriate, maybe the plugged pcv theory applies if oil could get past these without blowing out the dipstick?

What I was getting at with the warm engines was the way the oil cooler and filter housing work. Once that system is at full temp, the thermostat opens up in the housing and lets a cetain amount of oil pressure by. If there was a small leak in this system (includes hoses!!) the pressure doesn't build up enough and it could trigger your light.
??

I am not going to say anymore b/c I realize I am not very familiar w/ your engine.

Bill()C · #6 08-18-2008, 06:29 PM

FYI on the dipstick... It did actually push the dipstick out of the tube.

I don't know of a thermostat for the oil cooler. I don't see where it would be, but don't doubt that there would be one. I do not believe I have a leak from the oil cooler hoses, could be wrong. Hard to tell. The IP oil leak puddles in an arm/motor mount.

I checked the vent tube from the valve cover to the air cleaner and it is clear. Not sure where else to check in the crankcase ventilation system as this is the only part I'm aware of!

In any case I took a look at the oil filter and the upper portion had noticeably collapsed. I'm not sure if this is normally the case as a filter gets used that what is closest to the riser tube (um, lacking proper terms here) morphs from a nice round internal part to a bunch of wet newspaper. The filter is not old at all, but maybe I got a bum one? In any case I changed it and will drive the car tomorrow and see what we get.

On the chance that it is the filter I'm assuming that oil was being pumped up to the top of the filter but could not go any further???? I guess perhaps even the bypass would be clogged??? Haven't spent the time to figure out exactly how that setup works. It looks the same as the 70's 300D oil filters.

I will report findings back. If anyone has any ideas on where to stick some test gauges in the meantime I'm open to thoughts... like vacuum gauge on the main vacuum line, etc., etc.

Thanks again,
Bill

Bill()C · #7 08-18-2008, 08:25 PM

Further info... Just a short trip to the store tonight and I got the low oil indicator light. So apparently the oil filter is NOT the culprit.

Twice in a row the oil indicator light went dark while cornering... not sure if that's coincidence or not. Unfortunately by the time I stopped the oil indicator light was out. No oil had been unceremoniously vomitted.

I'm considering putting the vacuum/pressure gauge on the crankcase vent or the oil dipstick tube to monitor while driving.

Thoughts?

Bill

LUVMBDiesels · #8 08-18-2008, 08:52 PM

It is the PCV system. Something is blocking it and te pressure is building up. if it did not blow out the dipstick tube the engine would eventually stall.

jt20 · #9 08-18-2008, 09:51 PM

is your oil level good, perhaps too high?

Bill()C · #10 08-18-2008, 10:25 PM

Oil level has been within range on the dipstick.

LUVMB: What else should I check besides the tube? It's clear and the elbow coming out of the valve cover is clear. Not sure what else to check.

Thanks,
Bill

kerry · #11 08-18-2008, 10:32 PM

It's another case of mysterious spewing oil. There's no definitive explanation in any of the cases to my knowledge except for a case in which a member deliberately blocked off the crankcase vent, causing the spewage.

RML · #12 08-18-2008, 11:04 PM

Just a thought - have you ever broken an O-ring that dropped down into your oil filter housing or somewhere else and could have gotten lodged somewhere? Don't ask why I thought of this.

bbboomer · #13 08-18-2008, 11:50 PM

I may be all wrong here but here are a couple thoughts.
I don't think the oil filter collapsing is a good sign. At the same time I don't see how that would cause oil to spew from the dipstick. It certainly could cause the light to come on if the flow is restricted.
I think the spewing problem is with the crankcase ventilation or overfull of oil.
You said the oil is where it is supposed to be on the stick but do you actually know the levels on the stick are correct from installing the correct amount and verifying the level with the dipstick. Has the dipstick or tube been replaced?
When you checked the vent hose did you just check the elbow or did you check the entire hose, including where it connects at each end? Is there oil build up in the air cleaner housing? That would indicate the hose was open at least.

LUVMBDiesels · #14 08-19-2008, 10:03 AM

Quote:

Originally Posted by bbboomer

I may be all wrong here but here are a couple thoughts.
I don't think the oil filter collapsing is a good sign. At the same time I don't see how that would cause oil to spew from the dipstick. It certainly could cause the light to come on if the flow is restricted.
I think the spewing problem is with the crankcase ventilation or overfull of oil.
You said the oil is where it is supposed to be on the stick but do you actually know the levels on the stick are correct from installing the correct amount and verifying the level with the dipstick. Has the dipstick or tube been replaced?
When you checked the vent hose did you just check the elbow or did you check the entire hose, including where it connects at each end? Is there oil build up in the air cleaner housing? That would indicate the hose was open at least.

I agree with what you are saying here.

I wil llook at my SDL this afternoon to see how the PCV system is routed. It could is that he has a clogged oil separator and the pressure is building at that point. I cannot imagine what would cause an oil filter to collapse. The amount of pressure to do that would probably stall the engine, not just spew oil.

Bill()C · #15 08-19-2008, 05:18 PM

PCV Tube: I did take off the tube and the elbow and blow on one end and felt the air easily on the other. I didn't blow hard, in my opinion there's zero restriction in either.

Overfilled with oil: Possible my dipstick could be off, but I'm surprised that would cause ALL the oil to blow out.

Oil Filter Collapse: I might be overstating this and misleading. Looking up the middle of the filter the top portion wasn't perfectly cylinderical anymore. The walls still had integrity, but not it's original shape.

I do certainly think it's possible that something, a washer, O-Ring, etc got dropped in my oil filter housing at some point and who knows where this has gone. I say this because I did a couple of filter changes before I realized "Hey there's an O-Ring there."

I think I'm going to remove my dipstick and hook up a vacuum / pressure gauge tonight to the dipstick tube. Then I'll drive it to work in the morning and see what happens. I'll get readings that might coincide with the low oil indicator light. I'm just worried that I'm harming my engine driving it under this condition.

Bill