I wonder if you don't have an oil pick up problem. It looks like the way the oil sloshes is important. Do you have the level up to the full line? If not it might be interesting to fill it up to see if things improve, however, I agree that the pan has to come off, but if the problem is with the oil pick up, it might not be too expensive. I'm thinking the pump may be sucking air with the oil sloshed away from the oil pump, like if the pick up tube has come partially loose. This is just a WAG because I don't know what your pump arrangement looks like.

There have been new developments and I am afraid the prognosis is terminal. After confirming the bad oil reading, I pulled the old filter out of the box and gave it a close inspection under good light. Found chunks and fished them out with a skewer.

Photos below. Several similarly-shaped black pieces, non-ferrous, macro shot shows that they may not be metal.

More alarming is the shiny steel chunk of some cylindrical object, another bit of shrapnel, and a long curly metal shaving, all ferrous.

I don't know what they are but I know I will not run the engine again in this condition.

:(

Sorry to hear the bad news. :eek: What's the largest size of the debris? Have you inspected the oil pan that it is not crushed?

The parts are small; the corrugations on the cardboard are spaced about 5/16" apart.

How small? They had to be grounded through the oil pump gear teeth.

The oil pan is not crushed. It does have a small leak near the front from a scrape that occurred years ago and had been repaired with epoxy, a fix that lasted for more than ten years before the epoxy finally broke loose, causing a slow but manageable leak. A new oil pan was at the top of my list of repairs until this latest incident, I had already located one used and made arrangements to have the work done.

Didn't use the macro for this shot...

The odd-shaped pieces are some sort of plastic or Bakelite®, very dark ruddy brown under close inspection.

Attachment 122379

So-o-o...probably looking at a spun main bearing. No way to know the extent of the damage until I go inside the engine.

I know that the engine has to be loosened and lifted to remove the oil pan.

How heavy is the engine/transmission assemble; what rating jack/crane is required?

Preferable to lift from below and block the motor mounts--or from above using a crane?

What else has to be removed or disconnected to lift the motor?

Many thanks.

I can't help with 91 SDL specific questions. Wondering where the plastic and metal bits came from. Some vacuum pumps have bearings with plastic roller cages and vacuum pumps are known to grenade with age. IDK if that applies to the 91 SDL. Other parts that are plastic are timing chain guide and oil pump bellow/pickup.

Chain Guide & Tensioner
 

I'm going with Funola on this one, its probably peices of the timing chain guide. The oil pump chain has a guide and tensioner too I believe.

Here's a pic of what they should look like.

http://i61.tinypic.com/dmvc7d.jpg

You might try removing the valve cover to check the condition of the chain guides assuming they're visible from the top like an OM617.

Willson

Makes me wanna cry
 

You can take the Side cover of the Oil Pan off with the engine in the MB.

AND you may be able to get the Timing cover off "In situ" (Engine in Chassis)

BUT! As you can see R+Ring the Engine from the chassis is the way to go... And still stay sane!

(Me? I'd have the Whole Engine/Tranny system out,might be some parts that need "Freshening Up" in the Tranny system)


Here are gsxr's Travails with a "Regular" OM603 (As opposed to a 3.5L) [Same.Same Except 3.5L is "Bored Out" by MB] :

http://www.peachparts.com/shopforum/diesel-discussion/109058-om603-freak-failure-timing-cover-1987-300d.html

AND

http://www.peachparts.com/shopforum/diesel-discussion/231260-om603-vacuum-pump-explosion-bearing-intact-injection-pump-timing-device-wrecked.html

his updated URL (Pictures) :

http://www.w124performance.com/images/OM603_timing_cover/

____________________________________________________________________________________________________ _____

The Balancing act/Decision to be performed is:

1.R+R and Repair ( Disassemble and Totally clean the 3.5L) then rebuild it.
You'll come to whether this is practical for you as you talk to others who've
Done it.
AND How Much of a Rebuild you're in for.

2.Swap a "Known Good" OM603 3.0L in for the Damaged OM 603 3.5L.

3.Go Crazy and swap a "Known Good" OM 606 Turbodiesel into that Beautiful W126.
You'd use a Mechanical Injection Pump from a OM603 to do away with Almost All
of the OM606 Engine's Computer Crap.

I had previously made arrangements with a well-recommended local indy to replace my leaky oil pan, so was already prepared to open up the engine. The core that he was getting the oil pan from has a good bottom end.

The plan now is to remove the engine and have a good look inside, then determine the course of action. We can use the crank from the donor engine if need be.

The engine still starts right up and feels normal, no bad sounds or irregularity other than the oil pressure. It has seen minimal use since the problem appeared, and by driving VERY gently I was able to keep the oil pressure at a safe level, so I am hoping that the damage is limited. It is parked now and will stay that way until repaired.

Fingers Crossed
 

That you can get it Up and Running without Too Much !

Bummer