What is this part and/or what does it do?

It a small metal cylinder, looks something like an oversize inline fuel filter. It is ridigely attached the the exhaust manifold below the turbo on one end. There is a rubber hose attached to the other end.

The unknown part appears to be leaking oil but it could be a leak could be from somewhere else amd just dripping off the mystery part.

P E H

PE - I'll look under the hood of the '79 300SD after car talk goes off and post. Initially, I am wondering if it has something to do with the blowby/vacuum system. From memory, the '79 has a hose that runs from the turbo intake "u" tube to the vacuum pump to under/in the air cleaner housing.

__________________
Jim

PEH,
Hello, How have you been?
I believe what you are describing is the turbo wastegate which controls boost pressure. The tube provides a pressure signal, if you will, to the diaphram inside the wastegate which can be adjusted to increase boost as the spring inside there weakens with age.
Mine leaks a little too, doesn't bother me though.
Take care, Adam B