Jeremy, at 277K, DEFINITELY replace the vac pump. No question. It's a lot more expensive problem if it grenades. DAMHIK...

Rgds,
Chris W.
'95 E300D, 342K

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Objects in closer are mirror than they appear.

Have you personally experienced a high-mileage vacuum pump failure on an OM606 engine? Or known of someone who has? What is it that fails? Just curious, I haven't seen a lot of vacuum pump discussion on this forum except for the usual early-OM603 open-bearing problem.

A forum member stated last week that it was possible to retrofit some parts from the '98-99 E300D that would allow use of a later, sealed vacuum pump from the OM606 turbo engine. That would be a worthwhile mod if it is really possible.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

What are the signs of a failing vacuum pump? I can hear mine running when I cycle the door locks and sometimes there is a delay when opening the trunk using the inside switch (it opens when the sound stops). What extra expense would one expect if it grenades?

That depends on which car you have. The vacuum pump on the engine is different from the vacuum pump the operates the door locks in 124s, 126s, and others. That vacuum pump is in the trunk or under the rear seat. Failure would not damage anything else. You could have a failing pump or simply a leak that would cause the trunk lock to be slow.

The vacuum pump on the engine can, in failure, dump bits of steel into the timing case, potentially jamming the chain, which then breaks. This leaves one or more valves open to be crushed by their piston as it comes up to TDC. Engines have been ruined by such a failure although I suspect the risk is not all that high.

Early 124 diesels had a vacuum pump with an open ball bearing that could come apart but later models and all those retrofitted (like mine) have a sealed bearing. The 606 also has a sealed bearing.

I have been discussing this subject with forum member Sixto; our position is that, so long as the engine's oil has been kept clean, there is no reason, lacking a documented history of vacuum pump failure, to change the pump just because there are a high number of miles on it.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970