Well it is a 21 year old W126 with out a service history on a used car lot. It does have expensive issues and will probably cost you money. The oil leak is the least of your problems. 20 year old stuff will leak, a lot usually. I bet the power steering return lines are shot.

How about the suspension? Figure $1,500 their to rebuild the front end and do some work to the rear.

Brakes? I bet they are close to due. Figure a few hundred their.

The radiator and all of the hoses are probably original.

Flex discs?

If the engine mounts are close to original they are shot.

Tranns could blow, all bets are off at 20 years.

Just buy any old car expecting to put money into it. You have to want an old MB and be willing to put up with old car stuff to own one.

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2006 CL500
2009 C300 4matic
1969 280SE
2023 Ram 1500
2007 Tiara 3200