Turbo oil drain leak
 

I need to replace the oil drain gasket at the bottom of the turbo (1985 300TD), as well as the grommet and o-rings on the turbo oil drain tube. The gasket where the drain tube attaches to the bottom of the turbo is very hard to get to. Here is my question: at the bottom of the turbo, there is a cylindrical unit attached to the turbo housing (I think the waste gate hose attaches to it)...can I just remove this thing in order to easily get at the gasket, and just re-install when done? This seems to be very straightforward, but I don't know if I will upset any adjustments, or if there are springs or such that will be very difficult to get back together.

Thanks,

Mark

Oil Return Line
 

MarkM

The short answer is no. You cannot remove the cylindrical unit. It is part of the pressure control system and contains a spring and diaphragm attached to a valve inside of the body of the turbo.

I had the same problem with my 82 300 turbodiesel. There is a procedure to remove the oil return line without removing the turbo, but believe me it is wrong - at least for the Garrett turbo.

You could check this on yours by removing the bolts on the oil return line flange. Although you cannot see them, you can do this from above the car with flex sockets. Once the two bolts are removed, you need to rotate the flanged section 180 degrees in order to be able to have enough clearance to separate it from the lower tube. This is where I ran into difficulty as the cylindrical body of the control valve actuator inteferred with rotation of the upper oil return line.

The only way to separate the two tubes is to remove the turbo. I am in the process of doing this now for other reasons. See my last post for more info.

For my repair I gave up on trying to do the job without removing the turbo. In my case the gasket right at the turbo was not leaking, so I never took those two bolts off. What I found was that one turbo nut was loose, and most of the exhaust manifold attachment nuts. So, the turbo and exhaust manifold came off. It turns out a lot of the leakage down the side of my engine (on the 1982 300D) was drainage from the intake manifold. One gasket seals both intake and exhaust manifolds as they are in-line. The new manifold gasket is an improved design and does not leak. Turbo does not leak now either. Big improvement overall.

But the car was on ramps for a long time. :) While in there I did the POR-15 anti-rust treatment under the battery (and the battery plate too).

Originally I thought maybe that straight section of turbo drain tube would push downwards out through the oil pan opening. It doesn't. But now my oil pan does not leak either. :)

The main reason I have the collection of MB diesels is to drive one while maintaining or fixing up the other three. When you get down to just one that is driveable - its time to get serious with the repair efforts. :)

Ken300D