Went through a 'near catastrophy' experience shortly after acquiring my first 240D several years ago - not from an oil line, but when one of the two studs securing the oil-filter cap popped out of the canister.
Fortunatly it happenned in the daytime and I was able to see the huge puddle and trail in time as I backed out of the driveway. With no threads left in the canister, I wound up inserting a modified 8mm bolt from below after, discovering a similar repair had been previously made to the OTHER stud!

Happy Motoring, Mark

FYI
 

It's ALIVE and well.

Fabricated new 3900 psi cooler hoses.

These threads show how I do this repair at customer request.

http://www.peachparts.com/shopforum/2579908-post42.html

http://www.peachparts.com/shopforum/diesel-discussion/274623-oil-cooler-line-thread-size.html

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Bump
 

for Sunnyintx