Sometime after the first annual Mercedes Shop / Fast Lane Get together, my 84 300sd sprung a leak. I was on my way to work when my wife called saying she spotted oil on the garage floor. I quick check at the oil pressure and a banzai move into the first parking lot with the hood popped as I came to a halt revealed nothing major. The turbo oil return line had started leaking – top o-ring. Until I could get the parts I made a make-shift diaper out of a shop towel and zip ties
(pic 1).
I decided to do a couple of additional jobs as preventative maintenance since I would have the pan off to do the drain. First was the check valve after reading Dave Morrison’s excellent write up:
617 engine, replacing the oil separator check valve in the upper oil pan.
Second was to replace the strainer and boot that is at the bottom of the oil pump pickup. There is a post somewhere on the forum (can’t find it at the moment) showing a broken / torn boot.
Tips on the oil drain tube:
This is a royal PITA job. It took me hours of struggling to get the darn thing back in. I replaced the gasket under the turbo, both o-rings, the grommet at the oil pan and the straight oil drain tube
(pic 2).
First tip is to cut away the big grommet where the straight tube enters the oil pan. That will allow the tube to rock back and forth giving you the angles you need to get the tube out.
Second tip is to remove the heat shield that sits just in front of the turbo under the plastic air intake elbow. You will need all the wiggle room you can get to maneuver the tubes back in place
(pic 3 – taking out the shield) (pic 4 – more room!)
Part Numbers (for an '84 300SD - yours may vary!):
617-014-01-80 - oil pan gasket
617-187-10-01 - oil drain tube (straight - not the elbow)
617-187-01-85 - rubber ring (grommet)
004-997-53-48 - seal ring (o-rings x 2 qty)
603-187-05-80 - gaket turbo
007346-020001 - pin (believe this is the collar for the check valve)
617-018-00-29 - check valve
123-010-00-28 - oil pan
110-180-03-55 - strainer