Best oil viscosity for OM612 after 100k miles?

[mioba]

Can I ask why?

its a workshop tool. For measuring level only. not designed go be left in otherwise you would one.

 

[Botus]

aside for the usual ambient temps issue (and thus the need to manage driving style / engine load when running towards the end of those parameters in adverse conditons...), thicker oil was used mostly to make you feel better / maintain a bit more oil pressure on aged engines - drive well (warming the engine appropriately before giving it exercise) use the right oils, minimise short runs, use good oils and change regularly - then the "mileage" may be no indicator of wear

so 100k miles might be as good a new inside, whereas an abused 15k mile one may be trashed
with postive progression on stuff (before the prevalence of designed to fail took us back to the dark ages) 100k miles should be almost the same as new and thus the original specs for the conditions its mostly used in still apply

 

[charlysays]

I have always stuck with what my came with and rexomended at the time.
My W124 was only fed mobil 1 0w40 and after years before she succumbed to too much rust the engine was still clear as a whistle and it never used a drop and done 114k.
My W220 uses only mobil 1 0w40 turbo diesel, after 18 years it doesnt use a drop and on 78k
My W251 uses shell helix 5w30 and is on 60k now.
My W205 also shell helix and is on a poultry 22k.
Merc engines are pretty solid and I dont think they loosen to an extent that they need a different oil with age. The engine will outlast the car.

I tend to run the cheapest oil which still meets the spec and change it twice as often. This is on an OM605. I usually 10/40 semi synthetic and buy it in 20l tubs. It meets MB229.1 which is what the handbook calls for. Change every 5k, filter every 10k. Every OM605 I've had with mileages ranging from 100k to 250k miles has used oil, usually around 0.5-1l every 5k miles. lots of valves, lots of stem seals I guess plus a turbo. Never had one wear out and oil use was always stable.

 

[Gazwould]

The handbooks are stuck in time whilst oil R&D progresses .

You are missing out on the higher quality basestocks and better additive package of newer spec oils .

229.1 is **** poor .