... I had noticed some drips in the driveway, so I put the cardboard out overnight. In the morning, there was a significant oil splat on it. I crawled under the car and noticed that the bottom of the oil pan had an awful lot of oil collected on the bottom. There was oil collected on several bolts and other lowpoints as well. I could not seem to find any particular spot the oil was coming from. Where should I look for the source? I don't know the "anatomy" well, so I'm not sure where the usual culprits would be. There does seem to be a little oil collected around the oil cap, so it might be throwing it from there, but the cap looks good and there isn't a lot of oil tossed around on the top of the engine or hood pad. The oil level is OK, but a little low, so I'll add a bit this afternoon. Oil pressure has been fine.

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

Possible places to leak engine oil.

1. valve/cam cover gasket. (make sure 10mm nuts are tight)
2. Back side of head dime size drain hex bolt. (Need mirror to see)
3. Head gasket. (look atrear of head passengers side)
4. Oil feed tube to turbo from passengers side of block and under turbo.
5. Oil pan. (check 10mm bolts for tightness)
6. Aux side mounted oil pan. ( check 10mm bolts for tightness)
7. Injection pump to block large O-ring seal.
8. Rear main seal. (evident if leaking oil between at bottom of bell housing to block)
9. Front main seal (evident if oil around front main pulley wheel)

I hit most common areas but put car on ramps and look while engine is running.

Another very common source of oil leaks on the OM603 motors is the low oil level sending unit on the side of the pan.

Sounds like it's most probably the front crank seal. Wipe everything clean then look again after an hour or two of driving. If you don't see the source after looking all the places listed above it's probably the front crank seal. By the way, if it's your vacuum pump that is leaking it's time to change it. Come to think of it, even if it isn't leaking and it's the old style pump without the bolt heads on the front, it's still time to change it.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold