OK, so got to work on it today. I checked the chain first.

The notch is exactly in the groves of the cam mark. Camera makes it look off.



I look to be exactly 5 Degrees over.



There is a marking of paint on the chain... I've never noticed this before, I guess it was covered in oil.



The C clips are both on in the Vacuum pump. there is wear on the bearing.



And on the engine...

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Did you inspect the oil pump from below? Make sure its chain and tensioner are all in good shape...

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Looked fine. The rubber strainer was even soft and clean. Which surprised me because I fully expected it to be hard and was ready to replace it.

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Oil pump chain tensioner

__________________

see the coiled spring, that forces the tensioner. The design causes the spring clip to wear and fail.

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BINGO!

Man, I would have never found this till it was too late. You can see at number 1 where the plastic pieces came from.

Number 2 you can see the grooves that years and 320,000 miles has put in the rail.
The Clip has obviously fallen off and allowed the tensioner to shift against the upper pan. Number 3.



Of course the rail is NLA.. I have found it on Ebay and ordered one. I guess I'll have to find a clip at ace.

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Fortunately, BillGrisson has shared a how too on replacing this without taking the engine out...

OM617.952 Oil Pump Chain Tensioner Easy Replacement

Using BillG's guide above, I had the whole thing out in 10 minutes.



The tensioner rail is shot, as well as the spring (LOOK at how close it was to breaking!!!)



Even the shaft they all reside on took some wear...



Now, I have to locate a spring. I think I can get away with the shaft on the pump and reuse that spacer if need be. If I can find it, I'll get one. On another note, this also does NOT look like the origin of the plastic pieces I found, still leaning toward the lower timing guide rails.

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Glad you caught this before your engine grenaded .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

If anyone is parting an engine, I need that spring... I'll take the bearing cap as well.

The main bearing cap can't ( reliably ) be interchanged from block to block unless you get all of the main bearing bores line bored / line honed.

The pin is removable however with it being bent it might snap off if you try to pull it out especially if you use a slid hammer pin extractor.

There is a method using a 1/4" thick steel bar with a hole drilled slid onto the pin as close to the cap as possible then welded to the pin. Two jacking bolts are then threaded into the bar so they contact the cap. Think of a steering wheel puller / vibration damper puller in reverse.

Yikes, makes you wonder what state the 617's rolling around with 300k+ on them are in internally.....mine had 322k when I sold it....

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

They are well known for being million mile engines, at 300 K it is just getting broken in. . .

mine has 307-ish on it right now and runs great, but this thread has got me very nervous all of a sudden, because I have that kind of luck when it comes to cars

__________________
2007 Dodge Ram 3500 Cummins Turbo Diesel 4x4
1994 GMC S-15 pickup 4.3 5MT
1985 300 SD
1978 300 CD
1962 220-S Fintail - awaiting restoration

Good you caught it. I had mentioned this possibility in post #9.

I suspect the reason M-B went with this complicated chain-driven oil pump in the turbo engines is to give enough volume to supply the oil-squirters which shoot at the underside of the pistons. I think some gas turbo engines also have squirters, so wonder how they provide similar high-flow oil supply.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans