I just changed the glow plugs in my 300SD. I used Kroil Oil and PB Plaster liberally with no problems. Doing the job without removing any of the injector lines is a bit tricky. None of my glow plugs were bad but I'm glad I changed them. At least three were very hard to get out and carboned up pretty good. I used the "screw them out of the carbon" technique which worked well. I didn't have the special reamer but I wish I did. I'll just have to wait til next time to ream out the carbon.

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Orland Park, IL
1985 300SD 215,000 miles