1.6 NA BLUE smoke out the exhaust

[dkmc]

Strange occurrence.....suddenly I'm getting smoke (blue) out the exhaust off idle, at the
first instance of rev-up and also after coasting awhile when I 'get back on the throttle'.

What could this be??
There is no excessive blow by or oil vapor in the cam cover breather hose.
The head was done (new valves, new guides, new seals) less than 20K miles ago.

I have heard that sometimes a valve stem seal can pop off the guide.....but can that
cause enough oil to pass thru between the guide and valve stem to cause noticeable smoking
out the back?? As in "blue cloud".....?

It starts cold VERY well and runs VERY well, so I can't think it could possibly be a broken oil ring, and I've never heard of any oil ring failures on these, but does seem to be using quite a bit of oil
lately......


Puzzled........

Thoughts?

[dkmc]

PS......
Since the smokes is blue.....I don't think it's passing thru the cylinder(s) or else it would
be black just like burnt fuel smoke........that leaves exhaust valve guides....oil sucking thru them and
passing along with the exhaust gasses.
Plus no hint of run-away from oil acting as additional fuel....

??????

[82vdub]

It will take a lot of oil going into a cylinder in a diesel before you will see blue out the tailpipe. Oil in a diesel engine is like thick diesel fuel.

Blue is typical of unburned, or poorly burned diesel. I would verify the timing and run a compression check to make sure. Improper timing can lead to blue smoke at times.

[dkmc]

It will take a lot of oil going into a cylinder in a diesel before you will see blue out the tailpipe. Oil in a diesel engine is like thick diesel fuel.

Blue is typical of unburned, or poorly burned diesel. I would verify the timing and run a compression check to make sure. Improper timing can lead to blue smoke at times.

I agree partly.
How would the timing suddenly change so drastically yet it starts and runs so well?
It even smells like unburned oil.....oil thats been heated into smoke but not burned in the engine.
Increased oil usage suggests there is oil getting in the exhaust ......somehow.

[82vdub]

You could have the timing belt slip, or the lower timing gear on the crank slip, or break the woodruf key. Or, another thought, if there's oil leaking anywhere, it could get on a manifold and burn off creating the smoke? But, in general, in a diesel, it takes a whole lot of oil consumption before it shows up as blue smoke in the exhaust. I had a VW diesel that used about a quart of oil in 150 miles. No hint of smoke out the tailpipe at all.

[dkmc]

I do appreciate your ideas.....but really.....oil burning off the manifold??
Your comments sound a little like the trouble shooting tips that come with a new coffee maker.
See the title of my post......blue smoke out the exhaust....

Believe me....I work on these cars and know the engines inside and out intimately, and I do know
the difference between smoke out the pipe and oil burning off the manifold.
I know that when the oil goes in the cylinders it burns and comes out either black or is not
detectable.....that is why the BLUE color has me puzzled.
In 30 years of driving VW diesels I have never saw one smoke blue out the exhaust, and this is not
fuel or a timing issue, I already know that.

I am asking if anyone knows of valve seal issues or if they will draw lots of oil thru the valve
guides if the seal comes off the guide.
OR...how they behave if an oil ring fails.
A bad oil ring with good compression rings will show nothing in a compression test.

[82vdub]

It's no problem. Even with the topic of having blue smoke coming out the exhaust, my thought was that if you are observing this as the vehicle is going down the road, it may not all be coming out of the tailpipe, since you can't see it. So, even though the original post said it's coming out the exhaust, I was only addressing a possible issue with blue smoke seen in the mirror, where someone could think it was coming out of the exhuast. Plus, nobody knows how much smoke there is either. You can call it basic troubleshooting, but it's very difficult for anyone to troubleshoot someone's exact issue, through text on a website. It is also nearly impossible to know someone's skill level with work on vehicles as well. Clearly, I don't know all the specifics of what you observe and don't know how well that information is conveyed through your text either. Nobody does, but you. That's just an issue with this type of assistance to others.

[Dakotakid]

Well, no. In around 1.5 million miles of driving these, I have never blown blue smoke.
But, I have known guys who are not meticulous in: fitment/installation of rings, honing procedure of guides, installation of valve stem seals. So, perhaps, getting huffy at those attempting to help is not good procedure either.

Let us know how it turns out.

[dkmc]

Here's a little huff for ya......
Around 10 years and.... oh.....200,000 miles ago I took the head off this engine and pulled the pistons and rods.
Then I built a 'machine' that bolts to the block deck and incorporates a heavy duty Dewalt 1/2"
drill, a pair of linear guides, a Sunnen rigid honing head, a DC servo motor, and a ball screw. I used this machine, along with a precision dial bore gauge to hone each cylinder .020 over, with proper cross hatch pattern, factory recommended piston to wall clearance and a max of .0003 taper from the top to the bottom of each cylinder. New .020 oversize pistons were fitted of course.
All brand name parts, Mahle, etc.

I didn't touch the crank because the main and rod journals had negligible wear after more than 250,000 miles. I did replace the rod inserts with standard size ones.
I rebuilt the head, new valves and guides, and machined seats.

The engine logged at least 250,000 miles after this procedure.

And then about 2 years ago, I did another refresh on the head only per my first post.
And only because the head gasket leaked oil around the area where the oil port comes up thru
the front of the head. I blame the fucking junk "stretch" rod bolts.
The valve guides were also worn, a weak link in this engine design.
So....NEW guides, NEW valves, NEW seals, new ARP HEAD STUD kit.
No more oil leaks or head gasket problems with the stud kit.

And now, maybe 15,000 miles later, the blue smoke appears.....sometimes intermittently.
So I ask the question about blue smoke....

But.....don't tell ME about "fitment" and "honing procedures".....etc.
I will tell you, you are not conversing with a backyard amateur here....
And as I said, I do recognize the difference between blue smoke out the tail pipe and oil
burning off the manifold....

PS: This engine is one of 4 I have rebuilt, probably logging well over 3? million miles total
combined after rebuilds between the 4 engines.
I have never experienced blue smoke before, but I do know quite well how to
hone cylinders, and instal piston rings, valves, guides, .....you get the idea.
Meticulous? Yes.....you bet.

Thanks for your time.

Well, no. In around 1.5 million miles of driving these, I have never blown blue smoke.
But, I have known guys who are not meticulous in: fitment/installation of rings, honing procedure of guides, installation of valve stem seals. So, perhaps, getting huffy at those attempting to help is not good procedure either.

Let us know how it turns out.

[Quantum-man]

As you are using more oil than previously, the blue smoke definitely engine oil. Could it be rings? I don't see why not, as the oil can be crawling around the surfaces, even of a diesel. Likely though, to be valve seals hardened and stretched, or even fallen off.
No spares branded, or not, are likely to be as reliable as the original old stuff, that needed to be 'over engineered', to get the cars through the warrantee period; especially after production of car/engine ceased

Funny thing about the 'silly' manifold comment, is that recently I had a 'fumes in the car' issue during a period of bad weather. Only at start up...
I raised the hood, and, watched, found smoke in the engine bay, during the starting 'puff' It turned out to be exhaust smoke blowing back along the car and climbing into engine area, and then it would be gone... But it was so hard to trace
Glad you saw the sense in keeping the perfectly servicable shells rather than replacing, merely because you had some new ones to hand...

[dkmc]

I do wonder about rings....but it starts and runs flawlessly !
IF it were a broken oil ring tho.....it might be letting oil past and still have good
compression and 'appear' normal.

It does seem to be getting worse.....

Hard to imagine that THIS much oil could pass thru the valve guide or guides even with NO
seals in place....

Stumped....

[bc]

Re-thread,
I just installed an engine/transmission in an '86 Golf. It has a rebuilt head and rebuilt engine. It was hard to get it going after the rebuild but it runs now. Unfortunately it too is blowing blue smoke and won't hold an idle. Engine shakes a lot too. I'm thinking pump timing since I know that mechanical timing is on point. Any thoughts?

[82vdub]

Likely retarded timing. Loosen the IP and advance it as far towards the head as you can and see how it then runs.

[bc]

That's what my thoughts too. The pump definitely got turned a bit during the rebuild process. I was just hoping that I got it back where it should be.
Thanks for the input 82vdub!

[bc]

Just had to turn the pump like you said and it started right up!