M642 – Euro 6 compliance
The M642 engine used in the G350 is being investigated in Germany for (hard to explain) high levels of emissions under certain driving conditions.
This triggers from my usual rant that Mercedes should have sold the G500 in the UK but also the question whether the engines need a software upgrade only (i.e. higher AdBlue consumption) or whether hardware needs changing as well.
There seems to be three version of the M642 sold in the G in the UK:
OM 642 DE 30 LA [211HP/ 540 NM] exists in Euro 5 (2010/ 2011) and in a Euro 6 version (2012 - mid 2015); and OM 642 DE 30 LA (LS) [245HP/ 600NM] from mid 2015.
Has anybody any more insight?
From the experience of VW drivers, don't get the software update that will be part of the re-call.. I am sure NOx emissions can be reduced through the more frequent use of EGR and larger doses of AdBlue. But in the VW case, the EGR valves then rapidly failed, leaving you in limp-mode.And VW is apparently not accepting responsibility. The present settings and software will have been based on 100,000's miles of testing and if it ain't broke, I would not get it fixed with a last minute, knee jerk software mod. It's been reported that MB is doing this because some cities in Germany are now thinking of banning ALL Diesels and obviously that would be a major loss of revenue for MB (taxis).. NOx is just a by-product of the higher-temperature, more efficient thermodynamics of the Diesel engine. NOx will revert back naturally to O2 and N2 , but sticking exhaust gasses back into the combustion chamber to reduce the amount of N2 and O2 is just wrong in my mind.
In any case, new non-naturally aspirated petrol engines with wizzy turbos are also reaching high combustion temperatures and higher levels of NOx, but no one is saying anything about those.
If you are concerned about emissions, switch to using V-Power diesel which contains a large proportion of GTL diesel and consequently produces little or no smoke. It also contains a good detergent pack to keep components like injectors and EGR valve clean.
Additionally. if your are worried about the new T-Charge, then TFL don't really have a clue about what engines are Euro 6. They think my OM628 is Euro-6 !
I have noticed many smoky Diesels on the road - some are even relatively new vehicles. Just one of those probably does more damage than 1000 running properly. Maybe those should be tackled first.
https://www.dieselnet.com/tech/engine_egr.php
No, I don't think you need any engine hardware modifications, unless maybe you are attempting to go from Euro-5 to Euro-6. In which case i don't know how that would even be ratified in the registration document, for the authorities to recognise.
Your 'Euro-6' engine will already have AdBlue injection and an EGR valve . It was found that, in the case of VW, the car would recognise when being driven on longer, out-of-town journeys and wind-down the amount of AdBlue being used. To address the emissions issues, the software updates, increased both the usage of AdBlue and also the amount of time and frequency the EGR valve was working , resulting in EGR valve failures, lower engine performance and a higher cost in replenishing the AdBlue more often. I was just pointing-out that the software update was not a legal requirement and to think carefully, before opting for any similar updates from MB.
My understanding is that both Euro 5 and Euro 6 cars are not compliant, as they have identical engines I would expect identical modifications.
I agree with you, no changes until Mercedes has issued documentation what can be achieved and that they guarantee the changes. And first of all it would be interesting to see the emissions in real driving conditions. An S-class 350 BlueTec (Euro 6 OM642) seem to have NOx emissions of around 400 mg/km, I have not seen figures for a Euro 5 version.
And I agree, everybody I spoke to thinks that the EGR technology does not produce significant emission improvements; the improvement come via higher AdBlue injection, to make a G properly Euro 6 compliant (200mg NOx/km in everyday conditions) the AdBlue consumption has to increase to 3l/1,000km [and that seems to be one of the issues, you need a 50l AdBlue tank to cover 10,000 miles].
The interesting part (and the reason for my curiosity) is that the Euro 5 OM 642 DE 30 LA appears to be identical to the Euro 6 engine, so probably only different software; therefore, I assume that if the issue an software update in the UK, the Euro 5 G350 will become Euro 6 compliant (main difference Euro 6 cars have a 24.5l AdBlue tank, Euro 5 cars 15l).
That assumes that documented software upgrades will offered in the UK. The car manufacturer with biggest NOx problem seems to be Range Rover.
Technically what you say about the compliance levels of the two engines may be correct, although are here any differences perhaps in the DPF or other exhaust components?
My point was with regard to London;: TFL will generally go by what is in the present registration document, whether it mentions Euro 6 or otherwise by date of manufacture/registration. I am not sure whether getting a software update will amend your registration document.
(Our new MINI diesel has 'Euro-6' written in the registration document, whereas my 400CDi says nothing and is assumed to be Euro-5 by TFL ! )
Hi Theo,
My GLS350 has a 642 engine rated at 195 KW or 260 HP. the registered NOx is 0.147g/kWh which is well within the Euro 6 emissions max of NOx 0.4g/ KWh.
I am not aware of any recalls regarding software ugrades.
My View
All this emission control is not really working??
Yes it does if cars are run on long journeys but around town like most vehicles are used for and say 10 mile trips all is wrong
Petrol catalytic converters dont really work well unless on a cruise or long run. Are the emissions worse with more toxic chemicals when cold and around town etc
Diesels with a particulate filter are fine on a dpd courier van doing many miles but the old diesels with nothing were far less toxic on short trips even if they did smoke a bit
A modern vehicle is better but i am unsure about being better on small trips. I think its a step backwards
With all the electronics vehicles should be programmed easily to know what is best
So many times i have tested vehicles which fail the emissions test for MOT. I know the car is running perfect but unless its been on a good run many super efficient cars are close to failing
My OM606 g wagon barely gets a reading. No its not perfect but it just does it from barely warm every time
Something said in that i think
Post up
Agree.
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I have no intention to do anything in a hurry, have been at the end of the queue with all G modifications. If I understand you correctly, the software update alone is not sufficient, it needs a modified engine as well. I was under the impression that the AdBlue injection does not interfere with the working of the engine, it is injected into the exhaust, the more AdBlue is being injected, the more Nox can be neutralised.
I agree, turbo/ direct injection for petrol engines will probably the next issue. Not keen being seen in an AMG but I was pondering whether to switch to a G63 before the model switch to avoid the unavoidable Diesel engine modification (if one intends to drive into London in a G in the future), Mercedes is selling new G63s at unusual discounts. However, I have this feeling that I would switch the Diesel discussion for the Petrol discussion and I prefer the traditional G-look in any case.