UPDATE:

After 12 years and 126K miles ownership of my BOUGHT NEW '99 300 ETD W210, I've yet to experience the; "every day electronic issues," among other disasters many seem to think all OM 606 W210s have.

As far as value goes? As of this date, the '99 300 ETD W210 I own has two buyers ready at retail plus $750.00. So much for the reports of W210 "diminished value theories."

Hmmmm.... just how many W210 OM606 diesels have some "self-proclaimed experts" actually owned?

8.5 second / 0-60 and up to 32 mpg highway, is just a whole lotta fun too!




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No disasters here with the 1996 E300D (W210, OM606NA) at 277,000 miles. The first owner got to replace a number of expensive things including the ACC blower and its controller. When we got the car at 248,000 miles all those small disasters had already happened and been fixed.

When the transmission was rebuilt a few years ago the mechanic had problems with the wiring at the NSS switch and I rebuilt that entire sub-harness a year later. That was the "environmentally friendly" insulation problem that hit most late 124s and early 210s.

One factory-caused problem is the damage to the power steering pump, caused by never changing the fluid. None of the factory services call for that so it was never done. When I changed the fluid at 248,000 miles, it was absolutely black and the pump was not working well, especially at low engine speeds. Since then I have completely flushed the system twice and it's working a little better. I suspect that I'll eventually have to replace the $400 pump but I'm waiting until I have no choice.

The engine has never been open. In fact, as this is typed, I'm in the middle of pulling the valve cover for the very first time so I can inspect the timing chain and check for stretch and wear. I don't expect to see any but you never know ("film at 11").

There was a thread here a week or two ago about replacing vacuum pumps "just because" and I'm still considering whether I should or not. It's not difficult, just another $400 part that may be perfectly good.

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

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

__________________
Objects in closer are mirror than they appear.

I saw a discussion like this the other day on another make list, one devoted to a particular model that has a massive rep for certain problems. Yet there are also people with the same MY make and model, on that list, who have 300-400k of mostly trouble-free motoring on their cars and could not be happier.

One poster made an excellent point: often people gravitate to these lists because they have a particular problem, or they have a problem car. It happens. It is only natural that people who have experienced serious issues, or are familiar with others who have, then tend to spread the gospel as they see it. People who aren't having problems don't generally sit down and post a message saying "Wow my car is running SO well, haven't spent a dime so far this year...." (ETC).

In some cases, this list seems to be prone to drawn-out dissection of problems, which might put the fear of god into someone who doesn't eat, sleep and drink these cars....

As the saying goes, YMMV. When you come down to it, each owner is really only qualified to deliver an opinion on the car(s) he has owned.

It's helpful to keep in mind that cars can very a great deal within their production runs. What holds true for one model year may not be completely true for a year or two later... suppliers can change, engineers goof in doing updates, right down to a single assembly line employee making the same mistake for weeks or months before it gets caught.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

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

__________________

"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

I hear two vacuum pump discussions in parallel - 1) should you replace an early style pump (open bearing typically identified by no screws on the cover) = YES! and 2) should you replace a late style pump when it's racked up miles = I don't know. I haven't read of a late style pump failure other than gsxr's experience during a dyno run.

Note that not all that glitters is gold. I've seen pictures of a pump with screws on the front cover yet with an open bearing roller. I think it was for sale on eBay so the pictures might not have been of the same unit. Probably the worst a cover without screws can do is leak oil sooner than later. It's the redesigned roller that's the relevant design improvement.

A nemesis of panZZer might make a practice of removing an old style vacuum pump at every oil change to examine the plastic bearing cages. Buy a new pump only when the cages start to disintegrate.

To the original point, I hear and read of problems with the 210 not specific to the 606. My primary info comes from my sister's and cousin's 210s. ACC control problems are less than rare but I suppose that's better than an evaporator failure. Neither has suffered a front suspension collapse. One is in a dry location, the other is in the tropics. Both are 4Matic wagons and the 4Matic systems have been flawless.

Sixto
87 300D

My 96 E300D has 317,000 miles and runs great. I feel I have a small vacuum leak as the transmission shift a little hard on occassion. I have checked the obvious hose connections but thought you might have some idea's on pump vacuum or other.
Thanks,
Ron Rountree

I've got a 98 E300 in the shop with 285k miles that I'll be pulling the cam cover to inspect the timing chain/guides as I can. From what I have seen (including the earlier w124 606) the chain tensioner is the one that will show the most wear on this application. On the 617 engine it has been my experience that it is the oil pump chain tensioner that will show the most wear.

I have yet to see one run to failure. If I see anything interesting on the 285k mile E300 I'll put some pictures up. Unfortunately, you can't change them out without pulling the head.

Are ya'll saying that the vacuum pump for the 99 E300 is a better design than the 95? There is a good bit of price difference. Is the vacuum pump on the 99 E300 designed to NOT dump metal into the engine upon failure?

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Jim