c220 cdi blue smoke from cold

[dan@cdi]

hi i have a c220 cdi 2002 when i start up from cold i get a little blue smoke .
this morning i fort i give it a little rev and the blue smoke keeped coming for about 10 seconds and then went .
1.the car has a straight through exhust on it so no cat etc so i dont no if it could be that ?
2.also the glow plug light stays on for about 1 min after started but only sometimes and this happens when the engine is hot as well .but the car starts fine and i am not going to change them if it starts fine because as people no they can snap off while trying to change them?
3.and the car has done 207.000 miles but never misses a beat and i check the oil it dont burn none at all ?

 

[st4]

I think you need a new glo plug but that won't cause the blue smoke. I suspect the exhaust system you have might play a part in this.

 

[panason1c]

I cant see how the exhaust system could have any bearing on causing blue smoke?.

I'd be more inclined to suspect slightly worn turbo seals are responsible for the blue smoke on start-up, when the engine is at rest oil can seep past the seals and accumulate in the turbo and when you start up the accumulated oil passes directly into the inlet manifold (via the intercooler) and burns off.

 

[Dieselman]

Well seein as you ave a blown glo plug I would fink that will be the reeson for the smoke at startup.

 

[panason1c]

Well seein as you ave a blown glo plug I would fink that will be the reeson for the smoke at startup.

Wouldn't a blown glow plug cause black/grey smoke...ie...unburnt fuel (if any, on a cdi engine which will start without g/plugs) rather than blue smoke which indicates oil is being burnt?

 

[Dieselman]

Wouldn't a blown glow plug cause black/grey smoke...ie...unburnt fuel (if any, on a cdi engine) rather than blue smoke which indicates oil is being burnt?

I think the O/p's interpretation of the smoke may not be fully accurate. If it is indeed blue smoke then it will be a bit of oil seepage past the turbo seals.

 

[Geoff A]

Could be a number of things on an engine with that mileage. Low compression giving incomplete burn on cold start-up (smoke clears as temp gradually builds in combustion chamber), lack of initial heat from failed glow-plug, mild valve guide wear letting a bit of oil past until warmed up, etc, etc.
But if it really doesn't use any oil, then its most likely to be improper fuel burn when cold. You could also have partially clogged injector nozzles, so run some injector cleaner through with a tank of diesel.
Fix the easy things first. Glow plugs - and while doing one, do them all, they cost only a few quid.

 

[dan@cdi]

it was a glowplug it was unburnt diesel on one glow plug i might do the turbo seals anyways as it has done some miles anyways thanks for your replys anyways
cheers dan

 

[Geoff A]

Nice one - but if you've cured the smoke and its not burning oil, I wouldn't mess with the charger unless its necessary