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Suddenly blue smoke while idling

Wladek

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Some mechanical engine basics about smoke:
1. No smoke / smoke with white little cloud that fastly disappear & no smell - engine is healthy, some moisture in exhaust system (mostly colder days, or during weather change).
2. No smoke, just black exhaust tip & smell of fuel - mixture is too rich.
3. White smoke, cloud don't disappear fastly - coolant in block/combustion chamber: problem with cylinder head (crack on cylinder head or problem with cylinder head or block surface, eventually engine gasket, maybe cylinder head was not properly torqued). Coolant in reservoir is dark, different than usual coolant smell & also level might be higher than should be, or even might be over-leaks.
4. Blue smoke, typical toxic smell, cloud don't disappear fastly, oil consumption more than 1l for 1k km - oil in combustion chamber: valve stem seals are bad, valves shafts are worn or dirty; piston rings are worn or cylinder walls need to be re-honed, of course it also might be problem with pistons (corroded/burned etc.).

Blue smoke for a couple minutes, after engine wasn't runing for a couple weeks/months/or years due metal parts thermal expansion- is ok, but smoke should disappear after engine is warmed up.

As for me your engine (engine block & cylinder head) need a closer look made by engine specialist.
Faster you will do that - healthier your engine will be in future.
 
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Joeneke

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So...

some extra info, some good, some... less good...

Let's start with the overall condition of the engine... the engine has been overhauled completely by an engine specialist, about 2yrs/2000kms ago. They changed really everything:

1. drilled out and honed cilinders and put oversized pistons
2. changed valves, grounded them, in one word, renewed
3. changed bearings...
4. cilinderhead flattened
...

In short, an overall overhauled engine, done by a specialist. I've put some pics of the before/after result...
So... I think this engine should be in excellent condition...

Next message will be the one with an update on the problems... With more pics and - if possible - some movieclips...
 

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Joeneke

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So...

this morning I started the engine... No blue smoke, no funny odors, engine was first at choke running bit higher, then just idling nicely like he always did before. So that means that it only starts when the engine is (really) hot and the oil is thinner...

Nevertheless the problem remains because the engine is wet at the height of the exhaust collector. And it's quite wet, not only a little bit...
 

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deQuincey

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please respond to simple questions:

is the smoke comming out through the exhaust tip ? or
is it coming from the engine bay area ?

if it is comming from the engine area and if you see that the engine walls are wet, clean them with paper towels, start the engine and trace the path of the oil

is the 1liter/1000km oil consumption something new (after the tuning) ? or
was it present before ?

which oil grade, and specs do you use ?
was it changed at the same time as tuning ?

regards
 

Joeneke

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So we also did a compressiontest. I will put the exact values later but there was a difference of 3kgs between the first three and the last three cilinders. We also did a leaktest on the second cilinder, pressure mounting till 12kgs, so, that means... cilinders damaged?

The small valvecover dang was talking about appeared to be a blind one?

So i also got some pics of the cilinderwall, see for yourself...

PS: anyone knows how to upload movieclips on the board?
 

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Joeneke

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please respond to simple questions:

is the smoke comming out through the exhaust tip ? or
is it coming from the engine bay area ?

if it is comming from the engine area and if you see that the engine walls are wet, clean them with paper towels, start the engine and trace the path of the oil

is the 1liter/1000km oil consumption something new (after the tuning) ? or
was it present before ?

which oil grade, and specs do you use ?
was it changed at the same time as tuning ?

regards
Okay,

1. smoke is coming from the exhaust, only when the engine is hot
2. no smoke from engine bay
3. no, the oil consumption was before the tuning
4. About the oil specs, good question, I didn't actually added oil, it is just that the oilmarker is low. I prefer to change completely the oil since i don't know if it's full mineral or half synthetic oil
5. No, the guy who did the tuning, didn't know about the oil specs, so he didn't add as well
 

Joeneke

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Some mechanical engine basics about smoke:
1. No smoke / smoke with white little cloud that fastly disappear & no smell - engine is healthy, some moisture in exhaust system (mostly colder days, or during weather change).
2. No smoke, just black exhaust tip & smell of fuel - mixture is too rich.
3. White smoke, cloud don't disappear fastly - coolant in block/combustion chamber: problem with cylinder head (crack on cylinder head or problem with cylinder head or block surface, eventually engine gasket, maybe cylinder head was not properly torqued). Coolant in reservoir is dark, different than usual coolant smell & also level might be higher than should be, or even might be over-leaks.
4. Blue smoke, typical toxic smell, cloud don't disappear fastly, oil consumption more than 1l for 1k km - oil in combustion chamber: valve stem seals are bad, valves shafts are worn or dirty; piston rings are worn or cylinder walls need to be re-honed, of course it also might be problem with pistons (corroded/burned etc.).

Blue smoke for a couple minutes, after engine wasn't runing for a couple weeks/months/or years due metal parts thermal expansion- is ok, but smoke should disappear after engine is warmed up.

As for me your engine (engine block & cylinder head) need a closer look made by engine specialist.
Faster you will do that - healthier your engine will be in future.
Wladek,

I don't know how relevant this answer still is, but:

1. Blue smoke defenitely, only on hot engine...

And yes, I think i will finally not open the engine myself, but go to the company that did the overhaul. The people who did the tune up are specialists in their job (they tune for a number of raceteams with M3's) and they are also wondering just what is wrong with the engine. They even proposed me going to Holland to have a look themselves.

Their theory: after an engine is bored out and honed, they should 'wash' the engine. they think they didn't and that's why now maybe some iron fillings scratched the cilinder wall...

Let's wait and see who's right and what happened...
 

Joeneke

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Let's see if this works...
So this was this morning, cold engine, high idling because of choke, no any strange things going on... No smoke, no bad running, just a warming up engine...

 
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Joeneke

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This is the clip with camera from the cilinderwalls

They said the colour is like there is some sediment on the wall indicating a leaking segment or oil scraper...

 

lloyd

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1. smoke is coming from the exhaust, only when the engine is hot
2. no smoke from engine bay
3. no, the oil consumption was before the tuning
4. About the oil specs, good question, I didn't actually added oil, it is just that the oilmarker is low. I prefer to change completely the oil since i don't know if it's full mineral or half synthetic oil
5. No, the guy who did the tuning, didn't know about the oil specs, so he didn't add as well


I am not fully certain that I understand your concerns or the magnitude of those concerns.

First, as to the engine oil leak from the front of the engine, your photographs suggest leakage from a stud or above the stud. This suggests the leak is from the cylinder head gasket or (far more likely) the valve cover/ valve cover gasket. A later post indicates you may have discovered a "ding" or depression on either the cylinder head or the corresponding valve cover, but that is not pictured. If the "ding" is too deep for the gasket to conform to the depression and seal the area, there are numerous easy fixes, from gasket sealant to epoxy to even welding and re-machining the area.
oil leak (1).jpg


oil leak (2).jpg


As to the "blue" exhaust smoke that only appears when the engine has reached normal operating temperature, the issue could easily be an oil with too low a viscosity, coupled with a problem valve guide or valve guide seal or even a valve stem. You describe the engine as having been "overhauled completely by an engine specialist, about 2yrs/2000kms ago." I would submit that perhaps your engine is not fully "run in" so that the moving parts, especially piston rings, can best conform to their corresponding mating surfaces (cylinder walls). For this reason, I would suggest that as you drive the car, your compression readings will likely change (i.e., improve) and perhaps even your leak down measurement will also improve. Although I would ordinarily conclude that 2000kms is sufficient operation to achieve the initial "run in," there are exceptions when, for example, the engine is first operated with high detergency synthetic oil rather than specifically designed conventional (non-synthetic) "break in" oil. Again, this is a guess on my part. However, sight unseen, given the relatively low number of kilometers on the engine, I would suggest changing the oil (even to synthetic 20W50) and to continue driving, perhaps on a trip to visit the Zuider Zee.












DQDREWM,jpg.jpg









 

Wladek

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As for me - your endoscope photo's showed, that it isn't the problem with dirty engine after re-honing, re-surfacing, because there is no vertical scratches on cylinder walls, but your photo's also showed that your cylinder walls are far from perfect surface (brown pitting, where re-hone scratches are not visible), i think it might be a problem combined with piston rings, that's why there is such difference in pressure on cylinders.
Maybe also piston rings gaps / piston rings are too big?
On hot engine gaps on piston rings are even larger, so it might have sense if matching with symptoms you mentioned.

Piston rings gap specs for 3.0 engine are:
Top: 0,3-0,5mm
Center: 0,3-0,4mm
Bottom: 0,25-0,4mm

Height piston gap for all three: 0,01-0,022mm
 
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lloyd

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As for me - your endoscope photo's showed, that it isn't the problem with dirty engine after re-honing, re-surfacing, because there is no vertical scratches on cylinder walls, but your photo's also showed that your cylinder walls are far from perfect surface (brown pitting, where re-hone scratches are not visible), i think it might be a problem combined with piston rings, that's why there is such difference in pressure on cylinders.
Maybe also piston rings gaps / piston rings are too big?
On hot engine gaps on piston rings are even larger, so it might have sense if matching with symptoms you mentioned.

Piston rings gap specs for 3.0 engine are:
Top: 0,3-0,5mm
Center: 0,3-0,4mm
Bottom: 0,25-0,4mm

Height piston gap for all three: 0,01-0,022mm
I did not consider the photos due to a small viewing screen. However, upon closer inspection, even without the newer images, it would seem that the cylinder walls were merely "rehoned" rather that bored and honed. If there was any reboring, it may have only been to remove the upper cylinder "lips" or to remove a taper unseen in the images. It would also seem that the original pistons were reinstalled along with (hopefully) new piston rings. Although I doubt this occurred here, the piston ring gaps may have been properly sized, but perhaps some of them were not staggered. That said, with the sharply defined crosshatch pattern, some minimal "break in" has to occur for proper cylinder sealing.








These images do not inspire confidence in the engine rebuild. Maybe only a "hone" to remove cylinder wall "glazing?" Color changes suggest there may be some lack of cylinder wall uniformity. If new piston rings were installed, depending upon their composition, there may be a very long break-in period. The original equipment chrome plated top compression ring was very hard and durable and also notorious difficult to "break-in" without a suitably prepared cylinder mating surface Some softer composition rings, e.g., "Deves," allegedly do not experience the same issues.










When all else fails, there is always Bon Ami cleaning powder down the intake.





https://www.speed-talk.com/forum/viewtopic.php?f=1&t=41827
 
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deQuincey

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Okay,

1. smoke is coming from the exhaust, only when the engine is hot
2. no smoke from engine bay
3. no, the oil consumption was before the tuning
4. About the oil specs, good question, I didn't actually added oil, it is just that the oilmarker is low. I prefer to change completely the oil since i don't know if it's full mineral or half synthetic oil
5. No, the guy who did the tuning, didn't know about the oil specs, so he didn't add as well
thank you, simple questions bring simple answers and thus lead to simple actions,

first, i can not see the videos, maybe you have to upload them as public instead of private or other way

as to the pictures, and your comments from the company that overhauled the engine, to my humble opinion speak no good about them, they forgot to clean ?

ok, my general opinion on a car is to know where you are, as to oils i would suggest change it immediately, use a semisynth 10w40, castrol magnatec would be excellent and easy to find in europe, cheap and easy to do, change oil filter, you will need 6,2 liters

when i overhauled my engine, after 1000km i did retorque the bolts, have you consider it

and a goog idea is to ask the responsible people to check this problem they apparently caused, good luck
 

Joeneke

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Well,

first of all thank you guys for all suggestions and support. Yesterday I did a new testrun with the car and problem still occurs, the engine even has a tendency to shake a bit as if one cilinder isn't operating. As Lloyd and deQuincey describe and suggest, it could be a simple reason for this engine to smoke (suddenly) and not run as it should, but I guess the best way to find out is to have a closer look inside. So that's what we're gonna do next, have a step-by-step (first valvecover, then exhaustcollector, cilinder head, ... ) disassembly.

Although I'm not a specialist nor mechanic, I do understand most of what's being said here. My thoughts when having a closer look at the pictures from the overhaul compared to what's been said by the previous owner was the same... If the cilinderwalls would have been bored out, why the markings at the top from the upper piston rings are still visible? The walls should be brand new and clean from whatever historic marking after been bored. So, some things don't add up and I think before taking the risks with oil etc, I want to have a very thorough insight of what is happening inside this beautiful engine.

Let's agree I will give you guys a detailed follow up of proceedings, since I'm not go na bring it to a specialist, instead I'm gonna bring a specialist to me to do the disassembly and diagnose together with me...

So, keep an eye on this post, there is soo much more to follow...
PS: I have changed the youtube clip to 'public'Hope it will help...
 

Drew20

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Have you done a compression test? I think that has to be done soon, if you haven't already. The oiled plug on cyl 3 indicates a potential issue.
If compression good and even across all 6 cylinders you have a stable base to work from, if it's down on one or more, then a leak down test is the next step. A leak down test can help diagnose poor ring sealing (or burnt valves or CH gasket issues)
From the description of poor idling and blue smoke at idle, my first thought would be valve stem seals. If it's valve stem seals I'd also expect blue smoke on overrun. (A high manifold vacuum sucks oil into intake manifold past stem seals.)
Valve stem seal issues could indicate valve guide issues (which is a head off job) or it could be just old rubber going hard.
Poor ring sealing can also cause a poor idle, but I'd expect lots of blue smoke on full throttle acceleration also.

The external oil leaks could be a number of things, as it's cyls 1-3 it could be the timing cover seals. One thing to check with the previous owner is that the upper timing cover was skimmed with the head. I've read that can vote overlooked and cause issues
 

Joeneke

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The external oil leaks could be a number of things, as it's cyls 1-3 it could be the timing cover seals. One thing to check with the previous owner is that the upper timing cover was skimmed with the head. I've read that can vote overlooked and cause issues
Don't really know where to find these covers, Drew...

Anyway, another thank you for all your advices, guys...

For now a small update on the smokey E9...

So I called the company which did the overhaul:

- they didn't bore the cilinders on request of the previous owner. Cilinders were still in their limits
- they just honed with a special machine
- they kept pistons, just put new segments and oilscrapers

They guy who did the overhaul suggested that what could have happened is that after being honed, the engine ran on too high rpm and the scrapers got damaged, they were 'flattened' as he said.

It doesn't, however, explain the difference in compression I told you guys about. And here's another very peculiar thing... The difference in compression is very strange, I told you about a 3kgs difference, but I haven't tol you the actual results. Here we go, be surprised with me:

cilinder:

1: 11,00
2: 10,25
3: 10,50

remember, these cilinders were 'wet' at their exhaust...

4: 13,25
5: 13,50
6: 13,00

After realizing the difference, I was completely bit surprised because of the high numbers for them last three cilinders... Even the first three cilinders are high, because I read that 12 is more normal. So next week we're gonna do some more testing, and we're gonna do an oilswitch and a check of the oil that comes out...

The people from the engine overhaul company also said there was an issue with the oil pump, which would work on startup, but not while the engine was running. Maybe an issue to keep in mind...

Keep you updated!
 
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