Technical Puzzling behavioiur -smoke

[Mauro Malvezzi]

Hi everyone,

as I wrote on my introduction in the newbie section, I am the proud owner of a 2008 Series 2 Multipla. The engine is the 88 kW/120CV 1.9 Multijet. The car is a bit long in the tooth, at 395k kilometres, and suffered two major failures, both involving a broken gear in the transmission, while cruising on the motorway. The ensuing mechanical mayhem made for 2 quite expensive trips to the nearest garage.

Anyway, I like the multipla so much, I bit the bullet both times, footed the bill for the garage, and had the transmission/gearbox replaced. That issue is hopefully solved.
There's one problem I can't seem to understand, though.
The car is used for the daily work commute, approx 15 km including a brief stint on a beltway that lets me rev up the engine a bit. Apart from that, it's mostly used in a urban setting, and then on the motorway for a bi-weekly trip of approximately 700 km there and back.
The car's oil consumption has slowly increased, and now is quite frankly through the roof - 1 liter every 800-900 km. This isn't however the bit that annoys me.
The car is sometimes very smoky. A dense, very foul smelling smoke. It usually happens after 5-10 minutes of driving, and is often accompained by strong vibrations/"hunting" of the engine, as if it were to come to a stop due to not being able to idle.
The puzzling bit of this story is - if I turn off the engine, and re-ignite it, the smoke disappears. Then, sometimes it comes back, some other times it does not.
Like, for the past two days, it simply did not happen.

Following jobs were recently (last weekend) done on the engine:

1.Replacement of rotten thermostatic valve (QUITE an adventure, but it ended well!)
2.Replacement of the EGR valve (I had already cleaned the old one, I chose to put in a fresh unit just for the sake of it)

Now, the general oil consumption is, I am told, probably due to worn piston rings, a thing to be expected in an engine with so many kilometers under the belt. It's a major bit of work and the financial burden is a bit too much, I have been procrastinating on that decision for a long time...if only I could do the job myself but that's a bit out of my league at the moment.

But how about the puzzling smoke puffs? Why? I'd like to solve that, for no other reason than that of not bothering pedestrians and bikers with my stench...

Thanks to everyone who will chime in!

Best regards.

 

[bugsymike]

Hi everyone,

as I wrote on my introduction in the newbie section, I am the proud owner of a 2008 Series 2 Multipla. The engine is the 88 kW/120CV 1.9 Multijet. The car is a bit long in the tooth, at 395k kilometres, and suffered two major failures, both involving a broken gear in the transmission, while cruising on the motorway. The ensuing mechanical mayhem made for 2 quite expensive trips to the nearest garage.

Anyway, I like the multipla so much, I bit the bullet both times, footed the bill for the garage, and had the transmission/gearbox replaced. That issue is hopefully solved.
There's one problem I can't seem to understand, though.
The car is used for the daily work commute, approx 15 km including a brief stint on a beltway that lets me rev up the engine a bit. Apart from that, it's mostly used in a urban setting, and then on the motorway for a bi-weekly trip of approximately 700 km there and back.
The car's oil consumption has slowly increased, and now is quite frankly through the roof - 1 liter every 800-900 km. This isn't however the bit that annoys me.
The car is sometimes very smoky. A dense, very foul smelling smoke. It usually happens after 5-10 minutes of driving, and is often accompained by strong vibrations/"hunting" of the engine, as if it were to come to a stop due to not being able to idle.
The puzzling bit of this story is - if I turn off the engine, and re-ignite it, the smoke disappears. Then, sometimes it comes back, some other times it does not.
Like, for the past two days, it simply did not happen.

Following jobs were recently (last weekend) done on the engine:

1.Replacement of rotten thermostatic valve (QUITE an adventure, but it ended well!)
2.Replacement of the EGR valve (I had already cleaned the old one, I chose to put in a fresh unit just for the sake of it)

Now, the general oil consumption is, I am told, probably due to worn piston rings, a thing to be expected in an engine with so many kilometers under the belt. It's a major bit of work and the financial burden is a bit too much, I have been procrastinating on that decision for a long time...if only I could do the job myself but that's a bit out of my league at the moment.

But how about the puzzling smoke puffs? Why? I'd like to solve that, for no other reason than that of not bothering pedestrians and bikers with my stench...

Thanks to everyone who will chime in!

Best regards.

Check my recent reply to "DPF Issues" it may be related.
Although if yours is high mileage and burning engine oil do not thrash it as you may cause more problems.
All this is assuming your model has a DPF as not every Country version does.

"My suggestion would be put a bottle of DPF additive in at next fuel tank refill,then with engine fully warmed up do a 30 mile trip on dual carriageway at around 50 -60 mph without stops if possible and in a gear that keeps the engine revs at between 2000 and 3000rpm.
After that, see how it behaves and if DPF particle count still high then it may be a more expensive fix, but try this first, as it has worked for many modern small diesels that are generally only used at slow speeds around town which is no good for them.
Note if your engine coolant temp doesn't reach normal(90degrees) quickly then this will aggravate the issue.
Also, if it does sort the problem you will have to repeat every few months or change your driving habits, as in faster longer journeys.
Let us know how you get on."

 

[Mauro Malvezzi]

Dear Mike,

thanks for your reply. I'll give that a try. Are any of the oil additives (liquiMoly and such) worth a shot, too?

 

[bugsymike]

Dear Mike,

thanks for your reply. I'll give that a try. Are any of the oil additives (liquiMoly and such) worth a shot, too?

Personally I just use Wynns diesel flush before regular oil and filter changes.

 

[Mike1alike]

It kind of does sound like the piston rings are worn out, but that might not be the case. It's clear that the engine is consuming oil by burning it inside the combustion chambers. There are 2 possible way for the oil to get inside combustion chambers: worn piston rings or worn stem valve seals +/- worn valve guides. You can find out which is the case by performing a compression test. If the pressure is low, the rings are worn out, if the pressure is on the high end, the stem valve seals are worn out.
Is that engine diesel?

 

[Mike1alike]

The fact that smoke comes out after the engine is running and not just on start up, kind of tells that the rings are worn out, though, but the compression test will tell you for sure.

 

[Mauro Malvezzi]

The engine is a diesel, yes; I've already "accepted" that it might very well be the piston rings, it's the erratic behaviour that really puzzles me. Like, a whole lot of smoke, I turn off the engine - smoke disappears. 10 Minutes without smoke, and then it starts again!
Is there any bit of specific kit needed to perform a compression test?

 

[bugsymike]

The engine is a diesel, yes; I've already "accepted" that it might very well be the piston rings, it's the erratic behaviour that really puzzles me. Like, a whole lot of smoke, I turn off the engine - smoke disappears. 10 Minutes without smoke, and then it starts again!
Is there any bit of specific kit needed to perform a compression test?

As you say erratic behavior, at that sort of mileage it is entitled to smoke and use oil a bit.
Try the suggestion I mentioned as it is cheap to do.
Compression test involves injectors or heater plugs out if applicable and special compression tester so not a five minute job.

 

[Mauro Malvezzi]

Update

Adding some DPF cleaner to the last fuel top-up, and changing the oil + an oil additive in the fresh charge of 5 L oil, seem to have cured the "stinky smoke" issue.
Car still uses copious amount of oils, but I can kinda live with that

 

[bugsymike]

Update

Adding some DPF cleaner to the last fuel top-up, and changing the oil + an oil additive in the fresh charge of 5 L oil, seem to have cured the "stinky smoke" issue.
Car still uses copious amount of oils, but I can kinda live with that

You may need to use the DPF cleaner/additive on a regular basis unless you can do more longer faster runs in the vehicle.