Disco 300tdi - clouds of smoke out the back : (

Just got home in a cloud of smoke again : (

This is now 2 months after starting this thread. It happened the initial time, and my partner said it happened once to her (but i could get no diagnostics) - now its happened one more time when ive been about.

The smoke is coming from the exhaust. Billowing out. I think the video i took was a complete red-herring. This is thick, and smells of burning tyers (ie certain oil and not fuel). Its white, not black.

Came on after going up a hill here that's called 'long drag' - ie long, not especially steep. Busses always get stuck on it when it snows.

Was going 50 ish, at about 2500rpm. Smoke came on when i took the engine off load.
Engine stayed smoking, to greater or lesser degrees, all the way home (sometimes pumping out, somtimes almost clear)



To recap -

Unlikely to be rings, right? Starts fine. Would also not be intermittent like this?
Unlikely to be stem seals?
Not the seals on the inlet side of the turbo, as there's no oil in the hoses.

So, its got to be either turbo exhaust seal, or, could it be head gasket? Do these ever leak oil into the combustion chamber?

Now that ive 100% confirmed that the smoke is coming from the exhaust (and not external to the engine) its time to start changing parts.

cut (im sure you used to be able to delete posts?)

Right, after all this time, ive found a load of oil where its not supposed to be -

Took off the turbo > intercooler hose again (remember, i checked this before, and it was ok??)

Oil dripping out onto the chassis.





But...

Then i took off the air filter > turbo hose, and, more specifically, the breather from the cyclone unit, and got this -

http://s1277.photobucket.com/user/julianfincham/media/300tdi/VID_20150722_122256_zpsbsaqtzgz.mp4.html

(the background noise is not the engine running!)


Ive taken off the cyclone unit, and flushed it out with solvent - nothing odd there.
Ive checked the oil level (again) - nothing odd there.


Could that amount of oil in the breather pipe be attributed to normal accumulation (pooling at low points) and be ignored? If so, its turbo time.
If not, then what? And why so intermittent?

For good measure, here's a photo of the inlet side of the turbo.



Is that what they normally look like? I dont know.

There's only a little oil in the air filter > turbo hose itself (ie residue, rather than dripping, like the breather)

ps.

the inlet side of the turbo is certainly not dripping, like the outlet side is

julianf said:

Right, after all this time, ive found a load of oil where its not supposed to be -

Took off the turbo > intercooler hose again (remember, i checked this before, and it was ok??)

Oil dripping out onto the chassis.

But...

Then i took off the air filter > turbo hose, and, more specifically, the breather from the cyclone unit, and got this -

http://s1277.photobucket.com/user/j...0tdi/VID_20150722_122256_zpsbsaqtzgz.mp4.html

(the background noise is not the engine running!)


Ive taken off the cyclone unit, and flushed it out with solvent - nothing odd there.
Ive checked the oil level (again) - nothing odd there.


Could that amount of oil in the breather pipe be attributed to normal accumulation (pooling at low points) and be ignored? If so, its turbo time.
If not, then what? And why so intermittent?

For good measure, here's a photo of the inlet side of the turbo.

Is that what they normally look like? I dont know.

There's only a little oil in the air filter > turbo hose itself (ie residue, rather than dripping, like the breather)

Click to expand...

Definitely should not be "swimming" in oil. To help rule out one source or the other you can clean out the turbo inlet/outlet as best you can, bypass the hose from the breather cyclone temporarily into an old oil bottle, put a plug into the turbo inlet hose where the breather came out of, connect back up to the turbo then take the Disco for a drive/thrash.
By removing the hoses from the turbo after that test drive you will see if there is oil accumulated or not in either side of the turbo.
As I said a while back, my money is on turbo seal failure.

My trouble is that it seems to intermittent.

But...

As id purchased a new (used) turbo, im half way through swapping that over now anyhow (half way though as in couldnt get the downpipe bolts done, and now its chucking it down here)

If it clears up, i should have some movement on it later.

julianf said:

My trouble is that it seems to intermittent.

Click to expand...

From your vid of the exhaust (smoke) it appears as one could expect from a failed seal, that being, burning of droplets of oil sporadically, much of which may have depended on exhaust conditions, temperatures etc, those conditions could vary greatly.
Aside from that, it is definitely not normal to accumulate that much oil throughout the air induction system, you of course plan to completely wash the intercooler out before starting it up with the replacement turbo.

Its best to 100% ignore the video of the exhaust that i put up, as its not representative of the issue at all.

Possibly all its showing is cold engine start up smoke. Or it may be residual oil burning off from the incident.


When it happened the other day, we're talking not being able to see out the back window quantities. Proper smoke screen. Thick (white) smoke, stinking of burning oil.
Not some vague haze.


Intercooler - washing it out would be a good idea, i know...


Anyhow, the turbo is getting changed, but im still wondering if the oil dripping out of the breather is normal. As in, might it just have accumulated there, in a dip, over time, or could that be where its coming from, i wonder.

I fushed they cyclone unit with solvent and there was nothing obviously wrong there. I think theyre a static unit (ie no valves or anything to go wrong) so i cant see there being a reason for oil suddenly escaping that way.

So, yeah, with luck the turbo will sort it. There was just no point in me changing anything with it being so intermittent, before i found something tangible that 'could' be it.

f@#k

Changed the turbo for a 2nd hand unit.
Cleaned the intercooler

good bit of oil in there -


Cleaned the inlet manifold

Took it for a test drive. Smoke screen.

Got home (via some cyclists and a nice garden wedding reception : / )

Took off the turbo > intercooler pipe - dripping.
Took off the breather > air pipe - nothing
Took out the intercooler again - dripping


Cleaned it all up, and then did this -



(theres a small stab hole in the bottle too)

Blanked the port on the air pipe, and re-assembled.

Drove it about, up and down hills - a bit of smoke, but not so i couldnt see out the windows. Basically nothing significant.
Got home.

Checked bottle - clean
Checked pipework - clean


So, what's this all about then? Sure it has always been an intermittent problem, but this is starting to upset me now.

My plan -

Leave as is. Drive about as per normal. Keep an eye on the bottle and hoses. Maybe buy a k&n style filter to stick on the inlet manifold, in case it happens again too far away from home.

Any other / better suggestions?

julianf said:

Any other / better

Click to expand...

I dont really know for sure what regulates the oil supply to the turbo bearing housing but it is most likely to be a fixed orifice and that should not be able to change in any way, another thing that could cause you a problem is if the turbo bearing oil drain hose is in anyway restricted in it's flow path back to the sump, check that out it may have some sort of restriction that is "welling" up oil within the turbo bearing housing occasionally, the oil should flow away freely, also crankcase pressure could be a factor in this return flow, you could check out all the hoses and apparatus associated to provide ventilation, but from memory you have checked the oil filler off with the engine running and had minimal blow by.
With the steps you have taken already you have separated potential causes, but remember it takes only a small amount of oil being burnt in an engine to make a lot of exhaust smoke.
Only way forward is to keep plugging away, there will be an answer.

Ive been looking at the Cyclone separator.

Id read, on other forums, that it is a static unit, with no moving parts, however, it seems this is inaccurate.

This thread -

http://forum.landrovernet.com/showthread.php/34680-Cyclone-Breather-unit!?highlight=cyclone breather

has some photos of a cut open unit.

There is some confusion as to its operation, but my understanding is as follows -

a) whilst there is minimal -ve pressure in inlet tract (air filter > turbo pipe)

rocker cover vents to cyclone unit
cyclone separates liquid, which flows down to lower half of engine
gas exits, via normally open valve, to breather, and onto inlet tract (ie no liquid should pass through the breather)

then -
b) whilst there is greater -ve pressure in inlet tract, due to turbo spooling, and sucking air
normally open valve in cyclone unit closes to stop turbo dragging air from the rocker cover


But...

If that valve stuck -

c)
turbo would spool up, creating negative pressure peaks in the inlet tract
air would get dragged from the rocker, possibly too quickly for the cyclone to separate the oil



Now the above would fit with the intermittent nature of this. In my experience, when seals go, they weep, and that weep gets worse and worst. They dont (in my experience) *often* self heal.

Whilst a sticking valve? Seems a lot more likely.

Im going to go out first thing tomorrow morning and call in at the local parts place. It would be outstanding if the issue was a £10 breather unit - fingers crossed!