E55BOF

Good Evening all. I'm looking at buying an ML420 with the OM629 engine, but they're quite rare, and I can't find much information on them. .

I've read about the problems the V6 Bluetecs have been having with the oil turning to sludge, leading to seizure, but I presume the OM629 is pre-Bluetec and pre-DPF, so that particular problem shouldn't apply.

Does anybody have long-term experience of running an ML420 and can comment on engine reliability?

cohmoddersolo

Hi mate did you end up buying the ML420? if yes, how has your experience been with it? I am looking at GL450 (and I live in Australia). they have the same motors as the ML420 and I want to know how reliable they are!

E55BOF

Hello there. Yes, I bought it, and I've had no problems at all with it.It's a big strong powerful wagon; it's miles better than the W163, and with Airmatic the ride is excellent too.

The OM629 does have a particular Achilles heel, however; if it's used for short runs, it is very prone to sludging up the inlet tracts, and of course, the DPFs will also suffer. Not normally too much of a problem, but on the W164 the engine bay is so full of engine that anything- and that includes the DPFs, turbos and inlet tracts - other than fairly minor maintenance costs a fortune, because the engine has to come out. In fact, I've just sold mine because of that; I've not been doing many long runs, and I got sick of doing an extra ten miles on most journeys just to be sure...

I hope this helps.

kajtek1

We did not get to see those engines in America, but I guess generic advise for DPF use applies.
Get a scanner who can monitor DPF regeneration.
Most popular in USA is ScanGauge, who can monitor lot of things and be permanently plug-in, although with about $150 price sticker.
Lately Autel HT200 come on the market and Walmart sells it below $50. A bit harder to use, but than it is having more options and adaptations.
So having scanner you can observe particles build-up and regeneration status. When particles are coming close to 100% - you should plan longer trip (it is 10 miles on my car) to have good regeneration.
If you happen to have regeneration pending on short trip - take additional loop around the neighborhood till it ends.
It is OK once in a while to abort regeneration, who will restart on next drive, but aborting it few times in the row can lead to troubles.
For intake cleaning - Liqui Moly makes good stuff https://www.napaonline.com/en/p/AOCL...put=liqui+moly, although not easy to use. I already have it on the shelf, but my engines don't have any troubles (knock on the wood) so it is waiting its turn.
Enjoy the drive.