OM648 S320 cdi DPF cleaning?

[markben]

Greetings all on this helpful forum

My now 140k mile 2004 S320L cdi performs well with plenty of smooth power, good fuel consumption (31-45 mpg UK imperial / 25-37 mpg US) & rarely needs the engine oil topped up. Never any DPF warning light or limp mode problems, always passes an MOT (Annual Inspection) with no emissions issues.

The car leads a gentle life with daily approx 10 mile trips around town and a monthly 150 mile run on faster roads. With plenty of torque at low revs from the 3.2 cdi engine, I rarely need to ‘stretch’ it beyond about 3000 rpm.

BUT.. ! I’ve noticed that it does chuck-out some exhaust smoke under hard acceleration when I occasionally get the revs up above 3000 rpm. Not black smoke, more light greyish. All the same, it’s a bit embarrassing when I leave a bit of a smokescreen for …. following me!

I’ve read that that the car’s engine management ECU (?) should ‘passively’ regenerate the DPF in normal use, but I’ve also read about professional DPF cleaning services for ‘forced regeneration’

My Question: is it better to clear the DPF soot with more regular long, fast drives or have the DPF professionally cleaned? Or by some other method, e.g. fuel additives? Or... simply leave it alone?

Since the car runs so well otherwise, I don’t want to fix the occasional smoking problem by creating several other ones!

Many thanks as always

MB

‘The Best or Nothing’

 

[Blobcat]

It's very unlikely you have a DPF as it was ~2008 before the majority got them - you can do a vin check and look for option 474 - if it has that it has a DPF

 

[markben]

It's very unlikely you have a DPF as it was ~2008 before the majority got them - you can do a vin check and look for option 474 - if it has that it has a DPF

Ohhh.. thanks, I hadn't thought about that! Will check for 474. If it doesn't have a DPF, any other suggestions to reduce the smoke problem?

 

[markben]

Nope, no option 474....

 

[Wighty]

Nope, no option 474....

Put some injector cleaner additive in , put it in S mode . Give it an Italian tune up then report back if you
A … Have your licence still
B ….Have your car in one piece still
C ….Have less smoke from the exhaust

 

[markben]

Put some injector cleaner additive in , put it in S mode . Give it an Italian tune up then report back if you
A … Have your licence still
B ….Have your car in one piece still
C ….Have less smoke from the exhaust

Priceless! (good idea about the injector cleaner - hadn't thought about that )

 

[Larkone]

Try some 2EHN mixed into the fuel

2-EHN

Highest quality 99 pure 2-Ethyl-Hexyl Nitrate (2-EHN) cetane improver for raising the cetane value of pump diesel or bio-blended diesel fuels.

www.powerenhancer.co.uk

Makes them run more smoothly and less smoke I have found.

 

[markben]

Try some 2EHN mixed into the fuel

2-EHN

Highest quality 99 pure 2-Ethyl-Hexyl Nitrate (2-EHN) cetane improver for raising the cetane value of pump diesel or bio-blended diesel fuels.

www.powerenhancer.co.uk

Makes them run more smoothly and less smoke I have found.

Thanks! I'll try that.

 

[malcolm E53 AMG]

My old 100k miles OM613 engine (the predecessor of your engine) in my now long gone E320cdi needed an Italian tune-up once a month to clear accumulated soot etc out of the exhaust, a quick look in the rearview mirror and foot to the floor in second sorted it. Just a characteristic of the engine I’m afraid, EGR’s don’t help and fuel injector technology has moved on considerably since.

The OM613/648 is a gem of an engine run it as long as you can some of the advice above may mitigate soot etc

 

[markben]

My old 100k miles OM613 engine (the predecessor of your engine) in my now long gone E320cdi needed an Italian tune-up once a month to clear accumulated soot etc out of the exhaust, a quick look in the rearview mirror and foot to the floor in second sorted it. Just a characteristic of the engine I’m afraid, EGR’s don’t help and fuel injector technology has moved on considerably since.

The OM613/648 is a gem of an engine run it as long as you can some of the advice above may mitigate soot etc

Thanks Malcolm, I agree about OM613 & 648 engines. Many years ago I had a 1996 E280 (OM613 petrol?) which was as smooth as silk & felt bulletproof.

Love the idea of an Italian tune up - and regularly! . I probably drive my lazy 'S' too gently most of the time and, from what you & Wighty say, it just needs to really stretch its legs more often to keep it fit (like a Racehorse?). Thanks for the tips..

 

[Wighty]

Thanks Malcolm, I agree about OM613 & 648 engines. Many years ago I had a 1996 E280 (OM613 petrol?) which was as smooth as silk & felt bulletproof.

Love the idea of an Italian tune up - and regularly! . I probably drive my lazy 'S' too gently most of the time and, from what you & Wighty say, it just needs to really stretch its legs more often to keep it fit (like a Racehorse?). Thanks for the tips..

When conducting the Italian tune up , for full authenticity , it must be done with no seatbelt, silk shirt unbuttoned to the navel revealing chest hair and a crucifix, tight trousers and preferably a girl friend in the passenger seat .
Failure to observe these basic steps can result in the injector cleaner not working correctly

 

[markben]

When conducting the Italian tune up , for full authenticity , it must be done with no seatbelt, silk shirt unbuttoned to the navel revealing chest hair and a crucifix, tight trousers and preferably a girl friend in the passenger seat .
Failure to observe these basic steps can result in the injector cleaner not working correctly

... and as an extra precaution: wot about singing the lyrics to 'JUST ONE CORNETTO...' at the top my voice in a cod-Italian accent..?

 

[Wighty]

... and as an extra precaution: wot about singing the lyrics to 'JUST ONE CORNETTO...' at the top my voice in a cod-Italian accent..?

It can’t hurt buddy

 

[markben]

It can’t hurt buddy

Phew that's a relief. I thought for a minute I was being over cautious

 

[mioba]

04 W220, dpf was an optional item at build.
My 648 in my W220 gives a good puff of smoke when i floor it (not very often) if anything to clear it out.
If it aint broke - dont fix it.
Least hassle engine I have had, beyond servicing changed the plugs at 70k.
Its a graceful engine!

 

[markben]

04 W220, dpf was an optional item at build.
My 648 in my W220 gives a good puff of smoke when i floor it (not very often) if anything to clear it out.
If it aint broke - dont fix it.
Least hassle engine I have had, beyond servicing changed the plugs at 70k.
Its a graceful engine!

Thanks M. Yes, I didn't realise that my 2004 OM648 engine doesn't have a DPF. Duuggghhhh!

Thanks for the advice about 'flooring it' (!) sometimes to blow the cobwebs out. I do tend to drive mine very gently (around town mostly) at low revs: and that might be part of the soot build-up problem. Clearly, I need to stretch the engine more to keep it breathing well!

As you say / I know: in-line 6 cylinder OM648 engines are usually bullet-proof if maintained properly and (from what I've read) less complex / more reliable than the later V6 OM642 engines? Interesting that MB have reverted to In-line 6 cylinder engines for their latest models..?

Thanks again

 

[mioba]

I have a 648 and 642.
Hands down the 648 is way nicer.
642 is a great engine - but too many nuances.