If you can get to www.startekinfo.com from where you are, click on MB workshop resources then service manual library. Select model 124 service library from the list then load 124 disc 1 and find the section for 1987 300D which has the same engine as your SDL then proceed to the engine mechanical section. Let the pages load completely before selecting or it will make random selections. This is the most relevant section - http://www.startekinfo.com/StarTek/outside/12264/Program/Engine/602_603/01-5800hx.pdf but there might be steps along way you want to review.

Sixto
MB-less