Mercedes OM 601.940 - Revision?

Hello, dear forum,

I would like to briefly introduce myself, as this is my first post.
I work in mechanical engineering, not in the automotive industry etc.

Somehow, it turned out that I have a lot of old diesel cars on the property. I simply prefer older automotive technology much more than the newer one

Okay, for the specific case:

I have converted a Mercedes T1 208d beautifully into a camper. The vehicle has been driven for 15 years and has approximately 150,000 km on it. Current mileage is 200,000.

What happened. My dad is on vacation (he does this every year), and despite the strong, really strong smoke, he can still easily drive 500km... yeah, yeah, that's how it is.
Reason for the smoke: ZKD oil passage to cylinder 1. Unfortunately, it was running so that the oil level eventually dropped below the minimum. According to his statement, the oil pressure never came up. But who knows...

What do I want from the forum now?
I've disassembled the engine, and it doesn't look "soooo" bad anymore. But I'm not sure if I still need to redo the section.

I find it difficult to assess images accurately. The cross-cut is still well-preserved. One can only see tracks under favorable lighting conditions.

1.) In the upper OT area, the track is "blank" all around.
2.) There are some very light spots, almost like a "matt" finish.

Everything feels good with my finger. I haven't pulled the piston yet.
What else is there: The engine has exactly 200,000 miles. All 10,000 or higher quality oil with filter.
I replaced the timing chain at 100,000 km.

Well-maintained, but not pampered.
Since the bucket isn't a rocket, it will definitely run 80% of the distance on full throttle...

Okay, so sagen die Experten: Neue Kopfabdichtung anbringen und fertig. Or, should I continue to remove the piston and possibly overhaul the block?

Thank you all, and best regards,
Tobi

Hi,
The circular, smooth-running part at the top of the cylinder bore coincides with the reversing point. Here are different: the lubrication ratio, the temperature change, and the mechanical stress caused by the piston rings.
That would naturally become apparent with mileage, but it wouldn't be a cause for concern for me. Of course, you can measure the cylinder bores with a measuring instrument, but at a mileage of 200Tkm, I wouldn't see any reason to do so from the manufacturer's perspective.
hg
Herbert

Hi Herbert,


Yes, that's exactly the opposite.
Top. Thank you for your assessment.

Tobi

The career prospects look very promising to me.

Due to the low oil level according to the dipstick: My wife drives a Polo 6N where the crankshaft oil gallery was blocked. Oil was forced out of all openings. Accordingly, the engine compartment looked. Of course, she didn't notice anything and drove the car. When I accidentally discovered the mess, the oil level according to the dipstick was also below the minimum. I thought there was a major engine damage. But it's still running and consuming the same amount of oil, much earlier.

What I mean is: Just because the minimum level was reached doesn't necessarily mean that the engine didn't get any oil.

Hello,

The cylinder looks as it should, given its mileage. I would replace the ZKD and that would be enough.

Best regards, Rainer

Good morning,

And thank you for your responses.

Yesterday, I carefully checked the head with a hairline ruler, and it was absolutely not warped or anything. The engine is definitely living up to its reputation for robustness.

I am now proactively replacing the valve stem seals and timing chain with guide rails, etc. Then I will reassemble it.

Greetings from Tobii

Just as a warning – not to scare anyone – a lack of oil or low oil pressure would have been noticeable through bearing damage. However, before that, the rattling of the hydraulic lifters (if any are installed) would definitely have been noticeable. "Oil under MIN" means that there was still some oil left.
hg
Herbert