Carsy

I am surprised that my 2008 220CDI MB diesel collects soot on the rear bumper around the exhaust tail pipe .

It is noticeable after a tank of fuel. It has the particulate filter.My MB mechanic says that "they ( MB) are working on that "!!

I also notice that if you catch the Turbo Charger out that it will blow out some black soot.

Does the new Blue Efficiency 220CDI have similar characteristics ?

Ausmbtech

The Australian diesels don't have particulate filters on the cars, just the sprinter and 120cdi vito's.

that's pretty normal to get some some smoke from the exhaust on hard acceleration. It's due to soot buildup in the exhaust being blown out and a very large usage of EGR to reduce emissions. Using BP or Shell diesel will help a bit, Caltex is the worst for smoking in Australia.

The blue effiecency is quite similar the the previous generation cdi's

Carsy

You are not correct. The 2008 W204 220 CDI C Class has a particulate filter & has to use the low ash ESP lube oil. Just after the exhaust manifold there are two large canisters in the exhaust gas path.
Thank you for the other info. John.

240D 3.0T

If you are seeing ANY sot out the exhaust pipe, your DPF has failed. Being an 08, I'd imagine its still under warranty. Get the DPF replaced by the dealer, its a very $$$$ item you definately don't ever want to pay for yourself.

Ausmbtech

The 2 large canisters are the cats. Other markets got the DPF, we (Australia) didn't.

You can tell because the particulate filter will have a pipe on either side of the particulate filter leadind to a sensor (pressure differential sensor). The cat's have no such sensor.

The 646 engine (yours) certainly didn't, I have to check the new 651 engine in Australia (only started being delivered last month) as I'm not sure about that one yet for our market.

Carsy

AusMBtech, My apologies, there are no diff sensors on the canisters so you are correct in saying that there is no particular filter on Australian diesel 646 engines.

So that explains why there is a little grey haze under hard acceleration.

I suppose that as a owner driver I should be grateful that the car does not have a particulate filter. The engine may be more efficient over time( less backpressure) & it is one less thing to go wrong.

My next question is why is MB service pushing the use of low ash oils when there is no particulate filter? . Is it that the Mobil 1 ESP 5 w -30 is also a long life oil so making for longer change intervals?

Is there an oil in Australia to suit this engine & will give the engine long life ? . My last 20 Litre Mobil 1 Esp5w-30 drum cost me $240.It seems a $ waste to use an oil if it is too highly specified.I am quite happy to change the oil every 6 months & 6 or 7000km.

I appreciate your help,

John C.

Ausmbtech

The particulate filter on the Mb's is pretty good, if the correct oil is used then you shouldn't have any problems. It's not really going to be a problem if you do or don't have one.

You can use low ash oil, but it's not absolutely nessasary. If you local dealer also have light commercial vehicles or another brand that would have particulate filters then it would be in their interests to try a stock one oil that suits all models (DPF and non-DPF) which could explain why they are using it.

Personally I would just use Mobil 1 0w-40 and change it every 15,000km/12months. $12per litre for mobil 1 esp is pretty good, if you're happy with that oil then stick with it, it's approved for your vehilce and is reasonably priced. Don't do your oil changes too often though, it's a waste of money.

Just make sure you always use a genuine filter, they are worth the extra few$

Carsy

Ausmbteck , Thank you . This all sounds good practivcal advice. I have bought 10 genuine filters at a bulk discount so am set up for a while & will use the mb approved oil. At the end of the day peace of mind is worth a few extra dollars. John C.