Oil on plugs

[BimmerWill]

Last night I started changing the plugs on my car (231k) and only got to one last night. Cylinder 6 I pulled the plug out and this is what greeted me.

Going to do the rest this morning just thought I'd see what you all thought could be the source. I'm thinking vcg though it was changed less than 50k ago. Spark plugs were changed originally at 150k. If not vcg are we talking piston rings and/or valve seals?

Thanks everyone have a wonderful day!

[TheFinanceGuy]

ummm. Those do look a bit oily. I don't seem to be able to find a picture of my plugs from the ZHP, but these are plugs from my 944, after 50k miles

17856

When you see oil in the spark plugs tubes, that is normally the VCG- this... I don't know. hopefully others will chime in. I'm interested in knowing this as well.

It would only make sense to me, that it is worn piston rings- Do you find you are adding oil often in between oil changes?

[BimmerWill]

Pulled vcg off it was my culprit. Gasket is still good so I'm going to clean it up really well and use some gasket sealer to help prevent from happening again. Here's a pic of the valvetrain.
http://tapatalk.imageshack.com/v2/15/02/03/1865938781a87d3e202465c703198776.jpg

Not too bad for 230k lol

[wsmeyer]

A Leaking VCG won't get oil inside the combustion chamber.

First thing I would inspect / replace would be the CCV.

[BimmerWill]

Ccv was replaced less than 15k ago. I will check the rest of the plugs and see if they have any oil on them. I'm thinking oil snuck past when I took it out.

[wsmeyer]

I agree that there is oil on the threads but I think what we are seeing on the end of your plugs is burnt oil.

As Patrick pointed out, oil down in the spark plug tube is indicative of a leaky VCG. However, each spark plug tube has it's own gasket ring sealing it so it's unlikely you'd have it in more than one tube. If you do, I would suspect there is too much pressure building up inside the engine, which points to a CCV blocked or stuck closed.

Rando's was stuck open causing too much vacuum resulting in oil being sucked into the intake and then into the combustion chamber.

[TheFinanceGuy]

I agree that there is oil on the threads but I think what we are seeing on the end of your plugs is burnt oil.

As Patrick pointed out, oil down in the spark plug tube is indicative of a leaky VCG. However, each spark plug tube has it's own gasket ring sealing it so it's unlikely you'd have it in more than one tube. If you do, I would suspect there is too much pressure building up inside the engine, which points to a CCV blocked or stuck closed.

Rando's was stuck open causing too much vacuum resulting in oil being sucked into the intake and then into the combustion chamber.

Didn't think about that. Good point.

[Dave1027]

Rando's was stuck open causing too much vacuum resulting in oil being sucked into the intake and then into the combustion chamber.
I agree that it's the CCV but not too sure about the mode of failure. I would not think it's too much vacuum but maybe lack of vacuum or some kind of vacuum/pressure imbalance so that the ccv begins receiving oil directly from the dipstick tube. It could be that a pressure builds up in the crankcase causing oil to be blown out the dipstick tube, through the CCV and into the intake. If that's the case, a temporary fix for oil usage would be to block the hose between the CCV and dipstick tube.

[wsmeyer]

I agree that it's the CCV but not too sure about the mode of failure. I would not think it's too much vacuum but maybe lack of vacuum or some kind of vacuum/pressure imbalance so that the ccv begins receiving oil directly from the dipstick tube. It could be that a pressure builds up in the crankcase causing oil to be blown out the dipstick tube, through the CCV and into the intake. If that's the case, a temporary fix for oil usage would be to block the hose between the CCV and dipstick tube.

Definitely possible. We did not measure the vacuum on his before replacing it but I have tested it on mine that doesn't have any symptoms of failing and the vacuum pressure in the engine is very slight, less than 1" Hg.

Rando broke his old CCV apart and it's just a simple spring loaded valve in there that looks to me to regulate the vacuum pressure.

[Dave1027]

Rando broke his old CCV apart and it's just a simple spring loaded valve in there that looks to me to regulate the vacuum pressure.

So you must bust the unit to open it up? I read somewhere that somebody found that you can increase crankcase vacuum by connecting a vacuum hose to the capped off port on the CCV.

[LivesNearCostco]

Wouldn't anther failure mode be that the oil separator fails to separate oil, so oil sucked from the valve cover vent is simply being sent back into the intake and then cylinders instead of draining back into the dipstick tube? So yes if it's sucking oil from the dipstick tube you might want to block it, not if the problem is a failure to separate the oil.

My new CCV came with a blocked off vacuum hose port but I haven't cut open my old CCV yet.


I agree that it's the CCV but not too sure about the mode of failure. I would not think it's too much vacuum but maybe lack of vacuum or some kind of vacuum/pressure imbalance so that the ccv begins receiving oil directly from the dipstick tube. It could be that a pressure builds up in the crankcase causing oil to be blown out the dipstick tube, through the CCV and into the intake. If that's the case, a temporary fix for oil usage would be to block the hose between the CCV and dipstick tube.

[wsmeyer]

Based on how low the vacuum pressure is I'm guessing the separation is just done by gravity. I'm going to replace mine Saturday and I'll dissect my old one.

[Dave1027]

Wouldn't anther failure mode be that the oil separator fails to separate oil, so oil sucked from the valve cover vent is simply being sent back into the intake and then cylinders instead of draining back into the dipstick tube? So yes if it's sucking oil from the dipstick tube you might want to block it, not if the problem is a failure to separate the oil.
That's a good point. The only reason why I believe the oil comes from the dipstick tube is becase of reports of the CCV dumping so much oil into the intake that it hydrolocks the engine. You cannot get that much oil from the top of the valve cover. My only problem with that scenario is I don't believe the dipstick tube sticks down all the way down into the sump.

[Johal E32]

Well, those plugs are pretty darn old. They should have been replaced a LONG time ago. So it is possible that the old CCv left residue on the threads? And VCG would not cause oil on the threads from what I understand.

[wsmeyer]

Well, those plugs are pretty darn old. They should have been replaced a LONG time ago. So it is possible that the old CCv left residue on the threads? And VCG would not cause oil on the threads from what I understand.

Damn, good call, didn't even put that together when he said he replaced CCV less than 15k ago.

[wsmeyer]

So you must bust the unit to open it up? I read somewhere that somebody found that you can increase crankcase vacuum by connecting a vacuum hose to the capped off port on the CCV.

I can see how you can do that as the CCV works like this:



Intake Manifold
|
Pressure Regulator
|
Capped off outlet
|
Oil Separator
/ \
Valve cover Dipstick


So you're essentially bypassing the regulator.

I'm not sure why you would do that though. The engineers at BMW set the pressure for a reason and I personally wouldn't change it as I'm not sure what the ramifications would be.

[Johal E32]

Damn, good call, didn't even put that together when he said he replaced CCV less than 15k ago.

Yeah I think this is most likely the culprit OP. Start with a fresh set of NGK plugs!

[BimmerWill]

Oil on threads from vcg could have occurred when I removed the spark if there had been any oil pooling in the plug tube it would have made its way down the threads as I unscrewed it.

Also I mistakenly said 15k since ccv replacement it's been longer than that but I can't remember how long. I really need to keep better records.

I did notice when I pulled off the ccv tube from the valve cover there was a buildup of yellow jelly looking stuff on the inlet of the tube. Not sure if that's relevant or any help however.

[Johal E32]

Like this? If so, it is very relevant. I believe that means the CCv has failed. Can anyone back me up? Is that right? But I do know the CCV should hose should not have mayo or yellow looking gunk inside..

http://www.bimmerfest.com/forums/attachment.php?attachmentid=274573&d=1302776274

[Dave1027]

I can see how you can do that as the CCV works like this:



Intake Manifold
|
Pressure Regulator
|
Capped off outlet
|
Oil Separator
/ \
Valve cover Dipstick


So you're essentially bypassing the regulator.

I'm not sure why you would do that though. The engineers at BMW set the pressure for a reason and I personally wouldn't change it as I'm not sure what the ramifications would be.
I think it depends on how much vacuum the mod passes onto the crankcase. My opinion is lack of vacuum causes a number of bad things to happen like build up of crankcase vapors (mayo), blown gaskets and piston rings not sealing well.

[wsmeyer]

I think it depends on how much vacuum the mod passes onto the crankcase. My opinion is lack of vacuum causes a number of bad things to happen like build up of crankcase vapors (mayo), blown gaskets and piston rings not sealing well.

I'm confused. Are you talking about modding it to create higher vacuum than designed or a band-aid fix for a CCV not working properly?

[Dave1027]

Mostly a band aid fix. Basically, it could be that these CCVs only barely provide enough vacuum. Increasing it a small amount may provide an operating cushion.

[BimmerWill]

So does consensus seem to be failed ccv even though I've replaced it leading to the blown vcg also resulting in oil making its way into the combustion chamber via intake manifold?

[wsmeyer]

As Jordan pointed out that burnt oil could have come from your previous CCV.

[BimmerWill]

As Jordan pointed out that burnt oil could have come from your previous CCV.
Good point. I'm curious as to whether or not the 'mayo' in the ccv tubing is indicating the ccv is bad. I may just reseal the vcg and throw in the new plugs then check them later see if the situation reoccurs.

[wsmeyer]

Yeah, not sure if bad CCV causes mayo or mayo causes the CCV to fail

[Dave1027]

I would think the oil on the plugs from the previous CCV would have burnt off by now. Plus the oil on the electrodes looked really wet. My money is on another bad CCV.

[Dave1027]

Yeah, not sure if bad CCV causes mayo or mayo causes the CCV to fail

What came first, the chicken or the egg.

It's been said that the CCV is only designed to cope with so much moisture. First thing to check is the drain hose and the dipstick tube. It could be clogged causing everything to back up.

Also many people will say the engine needs to be run longer to burn up the moisture but moisture doesn't really burn up. It condenses and is dumped into the oil by the CCV. So in cold humid climates you need to run the engine longer and change the oil more often.

[alexandre]

Yeah, not sure if bad CCV causes mayo or mayo causes the CCV to fail

It's a snowball effect. Mayo = moisture in oil. CCV separates moisture from oil. Moisture accumulation leads to too much mayo, so bad separation, mayo starts being sent through the intake, i.e. you burn oil. Bad CCV pipes = more mayo, more mayo = pipes are more clogged. And then you wake up one morning and the mayo is frozen, so your CCV simply doesn't work. Cue the catastrophic failure where you shoot all your oil up the intake.

Mayo is normal in cold climates - mayo after driving spiritedly for an hour probably means CCV is on its way out.

[wsmeyer]

CCV separates oil from air. You want the moisture to stay in the air so it will be routed into the intake and not get into the oil.

[BimmerWill]

Alright I'll take a look at the ccv tubing and drain tube and see if its clear. I haven't been able to drove the vehicle much until recently so this would lead to a higher incidence of mayo from what I understand. Hopefully if its just clogged I can unclog it and stuff be good?

Its funny how a simple spark plug change can turn into a major diagnosis project lol

[Dave1027]

CCV separates oil from air. You want the moisture to stay in the air so it will be routed into the intake and not get into the oil.

Agreed. The only way to keep the moisture in the air is to keep the temps up so that it stays in gas form (vapor or steam). If the vapor hits a cold object such as the CCV it will condense into liquid water and dump into the oil. Maybe bmw should have designed heated CCVs?

[BimmerWill]

Apparently they have 'cold weather' ones which are insulated which is what I bought when I replaced it but all that has is just a little bit of insulation around the drain tube into the ccv. I'm dreading getting back into that thing again. They're a booger to get to lol.

[johnrando]

Yup, they are. GL and keep us posted.

[BimmerWill]

Got it back together around 1 this morning. Haven't checked ccv yet but there was definitely some mayo down the drain tube will be checking the dump tube for blockages and the unit soon.

[LivesNearCostco]

The CCV itself and at least 3 of the 4 tubes can be had in insulated versions. My CCV has a little foam jacket, which I managed to slightly damage while installing, but it's still wearing the jacket. On my original CCV, only 1 out of 4 tubes (the top tube that connects to intake air equalizer) was insulated.

Apparently they have 'cold weather' ones which are insulated which is what I bought when I replaced it but all that has is just a little bit of insulation around the drain tube into the ccv. I'm dreading getting back into that thing again. They're a booger to get to lol.

[alexandre]

Yeah if you're going for the cold weather version it's way easier to just pull the intake and do it from there.

[TigerTater]

Does one need to replace the CCV if there are no symptoms? And what would they be if there were symptoms?

[johnrando]

Besides the gunk in the hoses, grey smoke out the tail pipe, rough idle at times. It's such a pain to get to, I wouldn't until I saw symptoms. But, they do go bad so if you like working on your car, it's not expensive nor difficult, (just a pain because of location), you eventually will replace it, so not a bad preventative maintenance thing to do once the miles have added up.

[GOLDNSPOTS]

Don't reuse the VCG. Get a new OEM. They are only $65.


Sent from my iPhone using Tapatalk

[TigerTater]

Besides the gunk in the hoses, grey smoke out the tail pipe, rough idle at times. It's such a pain to get to, I wouldn't until I saw symptoms. But, they do go bad so if you like working on your car, it's not expensive nor difficult, (just a pain because of location), you eventually will replace it, so not a bad preventative maintenance thing to do once the miles have added up.

Thanks rando.