1987 300SDL - Rings

My 1987 300SDL has developed an oil ring related problem, according to my mechanic. The oil ring in one cyclinder is not functioning propoerly, which allows oil into the cyclinder. On cold start, the accumulated oil is causing a very rough idle. Is there anything I can do about this.
Paul Barbeau 1987 300SDL 133,000 miles

Oil doesn't flow upwards, what oil can accumulate in a cylinder from a bad piston ring?
If any lube oil is accumulating, which is doubtful, it's seeping down a valve stem because the plastic valve guide seal is worn. But doubtful.
Suggest you add some Techron or similar injector cleaner to the fuel and check that all the glow plugs are working.
Cold starts are the true test of the injectors, any minute bit of carbon or dirt will cause knocking and roughness. Don't get talked into some unnecessary work.

ummm... There is a shitload of oil splashing about in an engine while its running. the job of the oil rings is to scrape most of it off, so it does not get into the combustion chamber. Some oil is needed to keep everything lubricated.
This may or may not be so much of a problem with diesels, its not good for petrol engines though.
T.G. Lambach wrote:
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