Carsy

Could an Australian owner please give me details of the pollution system on the W205 diesels. Does it have a couple of cats & a DPF with ammonia injection? Thank you, John.

DBOC205

I know the diesels use AdBlue DEF. My spec came back as stating that the Aus cars were fitted with the larger DEF tank though. Not sure how long it's meant to last.

Carsy

Thank you for the info DBOC.

I am keen to find out whether only cats works in conjunction with DEF or whether a DPF is also in the system.

I am sure you will like the W205,it reads well. Which engine have you chosen?

John.

DBOC205

It's the high output OM651 .. Twin turbo 2.1l. Stump puller- 500Nm torque
Here's some info, but it's in German
http://de.m.wikipedia.org/wiki/Mercedes-Benz_OM_651

Carsy

With that torque do not be surprised how quickly your rear tyres wear!!.

I am a sedate driver but cannot resist a long steep ascent in the outside lane to see how well the diesel hang on at speed & under load in top gear :-)

Run it in well then enjoy it.

JC

jkyriakou

Om651 is a good Diesel engine. A little rattley at idle even though it has an unprecedented amount of counter balancing shafts!

This is a carryover from the 204 and I had this in my coupe.

Models built late last year has a timing chain tensioner seal recall so check that out.

The Bluetec models now use urea injection as well as DPF. Previously they had DPF only.

DerekACS

This tank holds 28L of DEF, enough for the annual service interval or about 15,000 km.

Of course to meet pollution requirements, the C250BT/E250BT also have a DPF.

Carsy

Thanks Derek, I don't know about the words " of course". I was hoping that the Australian W205 diesel engine did not have a DPF & no Australian owner has confirmed that it has.. My OM 646 does not have one for which I am grateful.

I find it difficult to understand why diesel W205 owners in Australia do not know what pollution controls their car has. They must be more interested in the colour ,sound system & other marketing nick nacks.

jkyriakou

If you saw my post above you would see the Australian model has a DPF. Euro 6 emissions are harmonized to Australian ADRs (or the other way round!) this means that Australian cars need to meet Euro 6 limits. The only way to do that would be with a DPF and urea injection. As we move closer to 2020 the standards are going to get so tight that PHEVs will become common like the C300 hybrid.

The OM646 was developed under Euro 4 standards hence no DPF (there were no limits) the OM651 was developed under Euro 5 and upgraded to Euro 6 with Adblu. With current tech I don't see the DPFs being a huge problem. You just need to drive your car for more than 20 mins in one go.

Carsy

jkyriakou,

Thank you for your welcome & in detail explanation of Euro pollution standards.

Does the latest diesel have 2 Cats in series?

John.

jkyriakou

There's 3 processes in total. The first cat is an oxidizing cat designed for monoxide and this is coupled with NOx adsorbers (deNOx system). The 205 has a DEF system so it also employs a selective reduction cat (SCR) which uses DEF injection. This takes care of any trace NOxs to meet Euro 6 and Californian emissions laws (50 state legal rather than 45 state legal)
In terms of "no of units" I haven't gone under the car yet, but would assume the oxidizing cat would be first, then a combined DeNOx and DPF and finally the SCR. After this the muffler.

If anyone knows for sure please let us know ..

Carsy

JK,

Thank you for the interesting info. The exhaust system certainly has them all lined up !!

Sounds as if it is even more critical to use the correct low ash oils with all that lot as it would be mind blowingly expensive to replace them all.

I wonder what their life expectancy is :-)

JC

jkyriakou

Agreed! They should last the life of the car as the rare metals are not consumed. Your biggest threat would be corrosion I would think. Salt, snow and living in the coast would be its enemy.

The DPF can fail and require regeneration but that should also last.

They will fail if petrol is put in by accident(I did this to my 204 but luckily didn't start the engine!) or excessive oil blowback (which being a Merc I would not expect)

And you can expect them to cost a bomb.

Weegs

Mate, I couldn't give a rats **** what pollution whatsymecallit me car has as long as she goes like the clappers.

Carsy

You might if it cost you a few grand to repair it, Weegso