Replaced the chain on my 91 300D today. Didn't check in advance how to remove the tensioner before starting, so I ended up removed the center spring loaded shaft.



With the spring loaded shaft and other parts removed should it be wide open? IE: should I be able to insert a screwdriver and touch the plastic tensioner rail? When I insert a magnet through the center hole there is something magnetic (steel) in the cylinder at the chain tensioner end. Looking in (the hole) with a mirror and light I can see what looks like part of the plunger.



My fear is unscrewing the part remaining in the hard could result in the broken shaft falling into my engine. The chain and tensioner rail blocks viability in the head or access with any tools.

I would have expected the end to be a smooth machine surface, mine looks more like something that broke and wore against the other 1/2 for many miles.







So is my tensioner shaft (plunger) broken?

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You've dis-assembled the Tensioner,not removed it.

Could the "Magnetic" part your magnet grabs Deep Down in the Bowels of
what you believe to be the Tensioner,ACTUALLY be the Metal operating end
of the Tensioner Rail ?

See picture #3.(almost, bottom Right hand.)

The FSM says to replace the Tensioner WHOLE if there is a problem with it.

Attached Thumbnails

     

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'84 300SD sold
124.128

what you see inside is probably the secondary plunger in the diagram posted above, it should come out when you unscrew the body.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Compress: Looking at picture #3 I agree that what I'm seeing is most likely the metal operating end of the tensioner rail.

You sir have solved the mystery and relived my fears, thank you!

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Zulfiqar: Using the exploded drawing Compress posted I don't see a secondary plunger. Based on that drawing the plunger (item 233) is what's shown in my photo with the ruler. Using the exploded drawing what is the item number for this secondary plunger you reference?

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233a is the Intermediate Rod
233 is the actual rod that does the "Work"

We can tell that 233 is the rod pictured by the OP 'Cause we can "See" the
Oil Return Orifice in the rod.(Marked as "b, return to oil pan" in the Schematic. My Picture #2)

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'84 300SD sold
124.128

Any recommendations for a replacement? Meyle and Laso are the two brands I see online?

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Agreed, that's why Zulfiqar's comment had me confused. Since both 233a & 233 are on the bench it appears nothing beyond the housing (235) remain in the head.

Thanks for the help.

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Internal and/or safety related, O.E. Mercedes ONLY.

BBBBbuuuT, Since the Tensioner is easily R+R ed I Might go with the Two brands
mentioned (After A.R. type Due Diligence on their Q.C. and return rate.)

Call Phil monday and ask him.

__________________
'84 300SD sold
124.128