I'm at a loss folks. I could use some advice as to what might be wrong here.

I've a 2008 R56 S. After idling 20 to 30 minutes the exhaust will begin to cloud with grey smoke (not really blue, not really white). After it reaches this point, higher RPM, either at rest or driving, will cause a billowing cloud of such smoke for the next several minutes, lessening over time and clearing up after 4 or 5 minutes. The car runs well despite this, with no obvious power loss or any other symptoms. The cloud doesn't appear during normal driving, only after a long idle.

Coolant is clean and the level has been stable for months. Oil doesn't leak a drop to the ground the view of the engine from bellow is clean. Oil levels drop at a steady rate of about a quart a month, which sounds like a lot of oil is burning to me.

The engine had several oil leaks in the recent past, but those have all been resolved (which is why I know its isn't leaking a drop. The valve cover has been very recently replaced with a brand new one to resolve a leak, and the massive leak from the oil filter housing gaskets was resolved when both sets (engine side and exchanger side) were replaced.

I'd suspect PCV, but since the valve cover was so recently replaced it seems unlikely. I'd suspect coolant in combustion, but like I say, the level is stable and the coolant is clean, ruling out a leak between the oil and coolant from a bad exchanger gasket.

I'll entertain just about any reasonable suggestion here. I could just use some ideas.

 

How many miles, and how has the car been maintained?

A turbo with worn bearings can cause smoke at prolonged idles, there is no seal inside them (they create a dynamic seal) and the best seal you get from them is when under load or turbine revs higher than idle.

But you could also be in for valve guide seals, they are rock hard on most cars we do head work on.

 

80k

Previous driver knew of the oil leaks but never fixed it. Just kept feeding it oil. I wouldn't be shocked to learn it was operated on less than ideal oil levels on occasion. Seems that would be bad for those turbo bearings.

 

I changed my oil this weekend. After, my car started to smoke at idle, and worsens to the point of doing the same as yours if it is allowed to idle for long periods of time. My wife drove it to work twice and the entire *** end of the car is covered in oil. I also have a cel with reduced power mode if I try to drive it like its a turbo roller skate. No codes stored. Is there any quick easy way to tell if the PCv system is plugged? I hate throwing parts at this car. Have 120 k miles on stock valve cover as far as I know.

 

Oops.... Why I am here in the first place.....
I worked as a diesel tech for Chevy for some years. I had a brand new duramax postal van do this exact same thing. After tearing the thing apart for days.... And tearing the engine down for inspection, and having an engineer from gm fly in to try to tell me I was an idiot.....but he couldn't fix it........ I FINALLY found a small piece of plastic about the size of a dime in the PCv crossover tube. It was flapping around in there and plugging the pcv system until there was boost pressure. I tested and inspected the living **** out of the pcv system.... Passed all checks. The line was clear when I put it to my mouth and blew through it. But it smoked so bad at idle the back of the van was black when I got it.

I have put on brand new defective parts many many times. I wouldn't rule out the PCv system in your new valve cover unless there is a definitive test to check it.

I'm going to tear into it this weekend and see if I can figure a way to condemn or rule out the PCv system. Then it's a catch can and new turbo I guess.....

 

If you just did an oil change and are now noticing oil slick on the back of the car I would recommend rechecking your filter and drain plug..

 

There is no oil leak. It's coming out of the exhaust.

 

If it's coming out the exhaust at a rate of leaving oil residue on the car I'd say you're in for a turbo.

If it's burnt oil (smoke), then you need to do more diagnosis.

 

Let me clarify my situation ... Sorry if I was too vague

The entire back of the cars painted surface is covered with black specs and spots. Looks like it hasn't been washed for thousands of miles or like the car did a 500 lap race in reverse....If you touch them, they smear and smel like burnt oil.

I've been searching the Internet and reading others posts. Looks like I need to test the PCv system for sure.

 

120k miles. 12k from me. Not easy miles from me. Unknown how it was maintained. I would not be surprised if it is the turbo. I just can't work out why changing the oil made it 100 times worse

 

These PCV systems don't clog, short of a crappy catch can that doesn't flow enough causing crank case pressure to build.

Let the car cool, check turbine shaft play, if you're using that much oil there will be significant shaft play.

If the turbine shaft checks out you need to get into compression and leak down tests and determine where the oil is passing through.

Also, if you're using that much oil I would assume you have oxygen sensor codes.

 

I have downstream o2 codes because of my cat delete downpipe.

No catch can yet... Never had one.

I have heard other people say these PCv systems fail and or clog quite frequently, hence the need to replace the valve cover.

While Im sure my turbo is worn, it can't see it just decide to start pouring oil into the intake between 2 drives while I was swapping the oil for cleaner, non degraded oil. Makes more sense to me that the PCv system failed from sludge, heat cycling, or whatever causes them to fail, and it's making excess crankcase pressure when idling. If I had swapped to 5/30 from 20/50 or similar, maybe then I would be thinking more towards the turbo puking oil.

the car is home now so I'm about to go try to figure something out.

My turbo rattles like a ***** until it warms up in the morning. The waste gate is loose on that arm inside the exhaust housing to the point it looks like you could almost just turn it around in circles even though it's indexed on there due to its shape.

Either way I am getting a new turbo as soon as I can afford it. I know it needs one.

The amount of smoke and the reduced power mode will prevent me from driving the car until I can fix whatever the cause is. It's pretty bad. If I have to put a valve cover on it....I will be forced to wait another month to replace the turbo. Too much money for my budget.

I saw a short video of smoke testing the valve cover that showed the difference between a bad PCv and a good one. Supposedly, it's not allowed to pass vapors out the passenger outlet with the engine not running. A new one doesn't. Bad one did.

 

Ok so I did some digging

No discernible shaft play on compressor side of turbo

OP, do you want me to get my own thread or is this discussion helping you too?

 

Mine was bad valve seals, and loss oil was due to cracked driver side pcv pipe it was leaking on sub frame so could not be seen on the ground, rebuilt the head changed the pipe yes $2180 but I got my mini back,no smoke and so far no loss of oil.
Ben

 

did you ever find out what it was? I have the exact same symptoms

 

In my case it was a bad valve seal.
Ben

 

[QUOTE=Bnourai;4328872]In my case it was a bad valve

was it intermittent?

 

No if you stoped at lights it would cloud the cars behind you.but you could not see any smoke while driving. Bad smell when you went in reverse all that smoke would get in the cabin.is had the head rebuilt and while all was a part cleaned all the carbon buildup it drives like new.
Ben

 

I'm thinking mine may be a programming issue, bad turbo seal or bad o2 sensors since it's commanding a really rich ratio 1.999 and pulling -20 st fuel trim even though the sensors say everything is in spec. Mine happens randomly every few days especially after a long drive then it goes away for a few days and comes back. I would be idling for about 10 min then it would start pouring smoke then I'd go for a drive and burn it off and I'd be fine for a day or so no matter how long I idled but still reduced power.
I just spent about 3500 to have the timing chain replaced, Evap purge replaced, leak detection pump replaced, vaccum pump replaced, leaking main seal and oil lines replaced.
The strange part is I pull the too rich at idle bank one code on my scan tool but the dealer pulls a lean code.
Im really thinking PCM.

 

after all you have done PCM maybe the problem,at first i thought it was PCM on mine too $300 later and that was not it,turbo oil line that was not it head job valve seal and problem solved.,,lots of guess's lots of $$$ spent..i have over $8000 spent to get my car the way i want it but that is not good enough.
Ben

 

I'm the same way! Something can always be perfected and it's these little technical snags that discourage most. luckily it's just a machine. We have the technology, we can rebuild him. I guess I'm in for a major overhaul if the pcm doesn't do the trick.
Happy motoring!
SS

 

This is classic to what I had happening. Your valve cover gasket is leaking. No oil hits the ground because it all burns off. Quite expensive to have this repaired at dealer (2400$)

 

Was it your intake or exhaust manifold? does oil flow through any section of the intake manifold? I could understand a leaking valve cover dripping onto a leaking intake gasket and getting sucked in but wouldn't that be noticeable as a vaccum leak?

 

When Oil first started disappearing I had the Dealer check for leaks but they couldn't find any (too small at that point?). Months later the leak became full blown with oil splattering everywhere. it was the valve cover.

 

Was your smoke coming from the engine bay or tail pipe? Mine is all coming out of the tail pipe for sure. I don't understand how a leaking valve cover could cause clouds of smoke from the tail pipe unless it was compounded with a leaking intake gasket.