2008 2.0d black smoke issues
 

Does anyone know what might be causing steadily worsening black smoke under normal conditions (except idle) on a 2008 c30 2.0d (no dpf)?

The car has done 140k and the black smoke has steadily increased from barely anything to quite heavy smoke under acceleration in the 30k that I've had it.

i have observed the following;
I've changed the fuel, air and oil filters every 8-9k since owning it. The black smoke significantly reduces for a few hundred miles and then steadily returns
During the first service, I noticed the oil was slightly gritty - I've not seen this since
The smoke marginally improves when using a fuel cleaning additive, albeit temporarily
Air filter is clean
It's not using oil
No error messages on the OBC

Any advice gratefully recieved. Can anyone with this engine and problem recommend a reasonable fuel additive or is it engine wear (I.e. Worn piston rings)?

Thanks in advance
Geoff

Hi I think it is the intercooler leaking,
have a look under the car, remove any panels under the rad/intercooler and see if it looks black and oily if so you need a new one, if you can not see anything get the car tested with a smoke leak tester, that will show any leaks,
Dave

Also check your EGR isn’t jammed open, that’ll cause black smoke. I blanked mine off and it’s drastically reduced the smoking. The EGR isn’t great on the 2d and they fail. Gritty oil deposits in the inlet manifold is normal on the 2d so don’t panic yet. If you’ve got the single inlet butterfly valve it’s worth giving it a clean and chamfer off the edges of the butterfly valve to stop it sticking, another known but silly issue.

TT

Thanks for your advice chaps.

Problem solved now - Blanking and electrically disconnecting the EGR seemed to do the trick, however I also found the following along the way;

Boost leak on the air inlet end of the EGR pipe. I Replaced the o-ring which reduced the smoke a bit and improved throttle response
The throttle valve was a little bit sooty and oily, and the inlet manifold was sooty. Throttle valve removed and cleaned and the inlet manifold was cleaned in-situ - again, this improved things a bit.

Next job is to fix the headlights - the reflectors have lost their shine! It looks like I'm going to have to buy the aftermarket replacements from retro lab