W210 320CDI Sudden Plume of Acrid Smoke... and all good?

[Irresistance]

Hello,

Jus a quick question and/or story on what happened to me today. I was finally in Germany able to give the car some speed, and after about, oh, 40 minutes of 130-180 KM/h driving (avg. of about 160?) I saw my car belch out the most disgusting, bluey-grey near-opaque smoke from the exhaust. The car seemed to marginally lose a bit of power for really a few seconds only, and after that - nothing. In fact, it seems, the car runs BETTER now, stopped (gently) vibrating in idle (while in D) and seems more quiet now.

Now - about 5000KM ago, I put in diesel injector cleaner, and went on a long trip to Italy. I am fairly sure that sometime towards the end of these 5000KM, something similar has occured, although the plume seemed to be less. At the time, I gave it the benefit of the doubt, and assumed it was someone else. Now I am fairly sure that was another such event.

So - my THEORY is that the driving fast has "uncrusted" some crap stuck in the engine/cylinders, and that plume was simply that crap being burned away. This is supported by these observations:

- The car seems to run BETTER now
- Diesel Injector cleaner has been applied first time after... oh... 50K KM? (it just ran very well all the time, but I forced myself to add it, finally)
- Streess/higher RPM (up to 3600RPM) which would shake things up
- Aside of the plume, NOTHING else is wrong - no limp home mode, no smoking, no smell inside, the engine sounds like new
- Because the car kept on going (virtually without a hitch), it is fairly reasonable to assume this is a single-cylinder event so to speak

Does anyone have a better idea? Of course I am going to go check it out but as an unfortunate circumstance I also managed to incapacitate my hood-opening-cable a couple weeks ago so until I visit my mechanic on WED, I cant even properly open the hood

All I can add is that the car runs very well, I've had it for over 2 years now, done 120K with it, maintain it by the book with all filter/fluid changes as dictated from Stuttgart with MB originals (yes, the mechanics always think I am nuts)

Thanks and Take Care

W

 

[television]

Yes it does sound as though it blew some crap out of the manifolds and burnt it.

 

[Alex Crow]

quite likely crud going through, yes.

not from cylinders though - it would be the build up from inside the inlet manifold, EGR and PCV products.

 

[Irresistance]

Thank you, case closed. Still will let an indie take a look... in general, would you advise a manifold reconditioning? I have heard some people do it and/or replace the plastic flaps with new (metal?) ones... is it worth it, from a longevity point of view...?

 

[television]

It would appear that it has cleaned itself out, I would just leave it, you have no warnings up

 

[Alex Crow]

as malcolm, probably no real need to get involved if all running OK.

 

[dieselman]

I suspect the Cat has coughed up a furball...