jafl

My '08 320 CDI (66k) is leaving a black exhaust stain on the rear bumper and body work BUT, here is the catch,
this is only happening on the drivers side!
As the single front exhaust pipe splits to two and then enters each muffler, why is only one side affected?
I recently towed my van for about 600klm over 4 days and the stain got progessively worse. When we travel to town (not towing) the stain is evident after app 100klm but nowhere near as pronounced.
The vehicle shows no fault codes, the performance seems to be fine and the mpg (19.6) is satisfactory, given the vehicle and the 2500kg van i was towing.
This has the local dealer stumped but it appears to me there may be a problem with one or the other rear mufflers - back pressure problems, blockage etc but why is the outcome as it is??
Can anyone assist?

Thank You

davey one

G,day Jafl, mine is the same! drivers side only! ,tip gets very black, only little get onto bodywork, I use BP ultimate only now using lower grade seems to makes more black on body,also pull a 2000 kg van

jafl

Thanks for your reply, davey one.

I only purchased the vehicle last November - private sale. Both the chrome/stainless steel tailpipes were jet black and took some cleaning. I noticed some staining on the rear chrome and, thinking that the position of the tailpipes (not extending past the rear of the bumper) may have been the cause, i removed the tailpipes and moved them back past the bumper by about 20mm.
This made no difference at all.
I always use either Shell or Caltex but in a ML270CDI i had prior to this one, i used BP a lot on vanning trips - but not exclusively. I had no exhaust stain on that vehicle.
There are plenty of 320 CDI's running around in the ACT and i haven't seen one with this visible problem.
What i don't understand is why there is black from one exhaust only, when they both come from a single pipe prior to the rear mufflers?
All i can think of is that i have a faulty rear muffler and if that is the case, which one?

Regards jafl

davey one

You could block off drivers side holding a rag over that side, feel the back pressure and then try pass side ,would maybe show you if pass side had a blockage? but at the end of the day if there is lots of soot coming down the exhaust could it be the exhaust (DPF) filters playing up? also are you using the correct engine oil.

jafl

Hi davey one.

• Will remove the tailpipe extensions and try blocking each exhaust in turn.
• Using Penrite full synthetic 5w/40 and or, Mobil 1.
• No particle filters on this model.

jafl

davey one

Gday, Jafi

Had a good look at the exhaust layout , and the bend on mine looks as though it feeds more to drivers side ! did not know 08s have no DPFs.

Dave

jafl

thanks Dave.
I will look at a few different things over the weekend and next week I will be needing a tank of fuel so will try the BP Ultimate - and see what the Gods have in store for me!

Cheers
Jim

iankayem

Mine used to soot also. But not to any extent that was of concern. I just washed it every week or so.

The W166 does not, but it does have a particulate filter.