Continued maintenance and repairs on the Mercedes 300D

Posted By on June 23, 2013

Since I’m on a car repair roll at the moment, I’ll continue to update the condition of my 1982 Mercedes Benz 300D Turbodiesel. replacedmb300dglowplugs1306It has come apart this weekend primarily to set the clearances for the valves, something that has to be done regularly and manual as this is a pre-hydraulic valve adjusting kind of car. Being that the cast aluminum valve cover has to come off and all the vacuum lines and crazy network of throttle linkages needs to be disconnected, it was the best time to access the glow plugs and remove the jury-rigged repair from last week (waiting on new part). I’ll include a photo of the failed throttle rubber bushing and rusted mount (below), and after looking at it decided that I really should have realized it was going to fail, but I’m live in the “if its not broken, don’t fix it world.”


After removing the throttle linkage, vacuum lines and fuel injector return lines, the valve cover came off easily with 4 nuts. The gasket between the cast aluminum valve cover and head is so much nicer than anything I’ve replaced in the past and the new molded silicone rubber one fit perfectly. Actually, I think I could have reused the old one, as it was in great shape and could have easily been reused … oh well, $13 for a new gasket isn’t going to be the item that breaks the bank.

After a quick inspection, I set to figuring out how my new Hazet wrenches fit. Some have plenty of access, other are a bit challenging to adjust. At first look, I thought, “man these are way out of adjustment?” Then I realized, oh … the feeler gauges need to be in “mm” not in “inches.” Whoops!

valvetrainmb300dFor the record, the setting for the 300D is .10mm for the five intake valves and .35mm for the exhaust while the engine is cold.



After all the valves were set, the next challenge was figuring out how to squeeze my hands and wrenches in under the fuel injector lines, etc in order to remove the glow plugs and ream out any excess carbon with a Kent Bergsma handy dandy reamer tool.


Besides the tight access to the glow plugs, everything was easy to do … just not as speedy as I thought … sort of glad I only had 5 of them to replace.


Desultory - des-uhl-tawr-ee, -tohr-ee

  1. lacking in consistency, constancy, or visible order, disconnected; fitful: desultory conversation.
  2. digressing from or unconnected with the main subject; random: a desultory remark.