Torque and release means exactly that. Set your torque wrench to 30NM and tighten until you reach torque. Break torque (release/unthread/back-up) on the DV holder, then re-torque to 30NM twice more. Set the torque wrench to 35NM and do a final torque setting.

The splined socket is sold by the host of this forum as well as in various other places. I picked mine up on Amazon for less than $20. Considering how many times my DV's have been in and out of my car for various reasons, that socket has earned its keep.

If you have the manifold off and you have no idea how long the glow plugs have been installed, it wouldn't hurt to change them out and ream the holes. Make sure you install a new manifold gasket if you do take it off. If you aren't missing out or nailing loudly when cold-starting, you likely don't have a glow plug issue. In that case, I'd do the DV seals without removing the manifold. Little trick that helps: Drop the socket down over the DV holder, then snap the wrench onto it. It's easier than trying to get the whole thing in there at once.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]